Metals and Non-metals - Class 10 Science - Chapter 3 - Notes, NCERT Solutions & Extra Questions
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Notes - Metals and Non-metals | Class 10 NCERT | Science
Understanding the classification and properties of metals and non-metals is fundamental to grasping basic chemistry concepts in Class 10. This guide provides an in-depth look at the physical and chemical properties of these elements, their reactivity, and practical experiments to illustrate these properties.
Classification of Elements
Metals and Non-Metals
Basis of Classification:
Elements are classified as metals or non-metals based on their physical and chemical properties. This classification helps us understand their behavior and applications.
Physical Properties
Physical Properties of Metals
Metallic Lustre:
Metals in their pure state have a shiny surface, known as metallic lustre. This property makes them suitable for decorative purposes, among other uses.
Hardness of Metals:
Metals are generally hard. This property, however, varies among different metals. For example, iron is harder than sodium.
Malleability:
Malleability refers to the ability of metals to be beaten into thin sheets. Gold and silver are the most malleable metals, making them ideal for jewellery.
Ductility:
Ductility is the property of metals that allows them to be drawn into thin wires. Gold is the most ductile metal, enabling extensive use in electronics and fine wires.
Conductivity (Heat and Electricity):
Metals are excellent conductors of heat and electricity. This property makes them invaluable in electrical wiring and cookware.
Physical Properties of Non-Metals
Comparison with Metals:
Non-metals generally have properties opposite to those of metals. They are neither malleable nor ductile. Instead, they are brittle and break easily.
Examples and Characteristics:
Some common non-metals include carbon, sulphur, and iodine. Most non-metals are gases or solids at room temperature, with bromine being an exception as a liquid.
Exceptions in Non-Metals:
Certain non-metals, like carbon in the form of diamond, exhibit unique properties such as extreme hardness.
Chemical Properties
Chemical Properties of Metals
Reaction with Air:
Most metals react with oxygen to form oxides, which are generally basic. For instance, magnesium burns in air to form magnesium oxide.
Formation of Amphoteric Oxides:
Certain metal oxides, such as aluminium oxide, can react with both acids and bases, making them amphoteric.
Reaction with Water:
Metals like sodium and potassium react violently with water, while others like iron react slowly or not at all.
Reaction with Acids:
Metals react with acids to produce salt and hydrogen gas. The reactivity varies among different metals.
Reactivity Series:
The reactivity series is a chart that ranks metals based on their reactivity with water and acids. This series helps predict how different metals will behave in chemical reactions.
Displacement Reactions:
Reactive metals can displace less reactive metals from their compounds. For example, zinc can displace copper from copper sulphate solution.
Chemical Properties of Non-Metals
Reaction Variances:
Non-metals generally form acidic or neutral oxides when they react with oxygen. They do not typically form salts with acids.
Formation of Hydrides:
Non-metals react with hydrogen to form hydrides. For example, chlorine reacts with hydrogen to form hydrogen chloride.
Electrovalency:
In reactions with metals, non-metals gain electrons to form negatively charged ions.
Metals and Non-Metals Reactivity
How Metals and Non-Metals React Together
Ionic Bonding:
Metals tend to lose electrons and form positive ions while non-metals gain electrons to form negative ions. This transfer of electrons leads to the formation of ionic compounds.
Formation of Ionic Compounds:
For example, sodium reacts with chlorine to form sodium chloride (NaCl), an ionic compound.
Corrosion
What is Corrosion?
Corrosion is the gradual deterioration of metals due to chemical reactions with the environment. Iron rusting is a common example, where iron reacts with oxygen and moisture to form iron oxide.
Methods of Prevention:
Corrosion can be prevented by painting, galvanising, anodising, or alloying the metal to improve its resistance.
Alloys
What Are Alloys?
Alloys are homogeneous mixtures of two or more metals, or a metal and a non-metal. They are designed to have specific properties that are superior to the individual components.
Importance and Uses:
Alloys like stainless steel, brass, and bronze are used extensively due to enhanced properties like rust resistance and strength.
Practical Activities and Experiments
Activities for Understanding Properties
Testing Hardness and Malleability:
Use a hammer to test the malleability of metals like gold and silver. Compare the hardness of various metals like iron and sodium.
Conductivity Tests:
Set up simple circuits to test the electrical conductivity of metals like copper and aluminium.
Reaction Experiments:
Perform controlled experiments to observe the reactivity of metals with water, air, and acids.
Recording Observations:
Maintain a detailed log of observations to understand the varying properties of metals and non-metals.
Conclusion
Summarizing the concepts of metals and non-metals, their properties, reactivity, and experiments, provides a fundamental understanding for Class 10 students. This knowledge forms the basis for advanced studies in chemistry and various practical applications.
By thoroughly exploring the classification, properties, and reactions of metals and non-metals, students can gain a comprehensive understanding of these essential elements and their significance in the world around us.
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Extra Questions - Metals and Non-metals | NCERT | Science | Class 10
In the given reaction, $M_{A}$ is a metal $A$ and $M_{B}$ is a metal $B$. Choose the correct options regarding the reactivities of $M_{A}$ and $M_{B}$.
$M_{A} +$ Salt of $M_{B} \rightarrow M_{B} +$ Salt of $M_{A}$
A $M_{A}$ is more active than $M_{B}$
B $M_{B}$ is more active than $M_{A}$
C $M_{A}$ and $M_{B}$ are equally active
D There is not enough information to determine which metal is more active
The correct option is A: $M_{A}$ is more active than $M_{B}$.
Explanation:
Highly reactive metals have the ability to displace less reactive metals from their salt solutions. In the given reaction: $$ M_{A} + \text{Salt of } M_{B} \rightarrow M_{B} + \text{Salt of } M_{A} $$ since $M_{A}$ displaces $M_{B}$ from its salt solution (i.e., salt of $M_{B}$), it indicates that $M_{A}$ is more reactive than $M_{B}$. This is because only a more reactive metal can displace a less reactive metal from its compound.
Write the uses of gold, mercury and zinc.
Number of animals is proportional to the Price
If two quantities are directly proportional, the ratio of the two quantities remains constant.
For example:
Number of dogs | Price |
---|---|
3 | 5 |
18 | ? |
By setting up the proportion:
[ \frac{3}{5} = \frac{18}{x} ]
Solving for $x$:
[ x = 18 \times \frac{5}{3} \ x = ₹ 30 ]
Therefore, 18 dogs correspond to ₹ 30.
Applying the same method to the other cases:
Number of cats | Price |
---|---|
4 | 9 |
16 | 36 |
For 16 cats:
[ \frac{4}{9} = \frac{16}{x} ] Solving for $x$:
[ x = 16 \times \frac{9}{4} \ x = ₹ 36 ]
Therefore, 16 cats correspond to ₹ 36.
Number of rats | Price |
---|---|
6 | 11 |
30 | 55 |
For 30 rats:
[ \frac{6}{11} = \frac{30}{x} ] Solving for $x$:
[ x = 30 \times \frac{11}{6} \ x = ₹ 55 ]
Therefore, 30 rats correspond to ₹ 55.
Number of rats | Price |
---|---|
6 | 11 |
30 | 55 |
For 21 lions:
[ \frac{7}{13} = \frac{21}{x} ] Solving for $x$:
[ x = 21 \times \frac{13}{7} \ x = ₹ 39 ]
Therefore, 21 lions correspond to ₹ 39.
So the individual mappings are:
21 lions correspond to ₹39
30 rats correspond to ₹55
₹30 corresponds to 18 dogs
₹36 corresponds to 16 cats
A metal has a large number of electrons but a non-metal has only a small number of electrons.
True
False
The correct option is B: False
A metal indeed has a large number of free electrons. The term free electrons refers to the electrons that can move easily within the material, facilitating electrical conductivity. In contrast, a non-metal possesses a small number of free electrons, which makes them poor conductors of electricity. However, in terms of the total number of electrons, both metals and non-metals have comparable complete electron configurations as determined by their atomic numbers.
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Ask Chatterbot AINCERT Solutions - Metals and Non-metals | NCERT | Science | Class 10
Which of the following pairs will give displacement reactions?
(a) $\mathrm{NaCl}$ solution and copper metal
(b) $\mathrm{MgCl}_{2}$ solution and aluminium metal
(c) $\mathrm{FeSO}_{4}$ solution and silver metal
(d) $\mathrm{AgNO}_{3}$ solution and copper metal.
A displacement reaction is a type of reaction where a more reactive metal displaces a less reactive metal from its compound.
To determine which pairs will give displacement reactions, we need to refer to the reactivity series of metals, which lists metals in order of decreasing reactivity. A metal higher in the series can displace a metal lower in the series from its compound.
Here's the order of the metals mentioned, from more reactive to less reactive according to the reactivity series:
$$ \text{Aluminium (Al)} > \text{Magnesium (Mg)} > \text{Iron (Fe)} > \text{Copper (Cu)} > \text{Silver (Ag)} > \text{Sodium (Na)} $$
With this in mind, let's evaluate each pair:
(a) NaCl solution and copper metal: Sodium (Na) is more reactive than copper (Cu), so copper cannot displace sodium from NaCl. There will be no displacement reaction.
(b) MgCl₂ solution and aluminium metal: Aluminium (Al) is more reactive than magnesium (Mg), so aluminium can displace magnesium from MgCl₂. There will be a displacement reaction.
(c) FeSO₄ solution and silver metal: Iron (Fe) is more reactive than silver (Ag), so silver cannot displace iron from FeSO₄. There will be no displacement reaction.
(d) AgNO₃ solution and copper metal: Copper (Cu) is more reactive than silver (Ag), so copper can displace silver from AgNO₃. There will be a displacement reaction.
Therefore, the pairs that will give displacement reactions are:
(b) MgCl₂ solution and aluminium metal(d) AgNO₃ solution and copper metal
Which of the following methods is suitable for preventing an iron frying pan from rusting?
(a) Applying grease
(b) Applying paint
(c) Applying a coating of zinc
(d) All of the above.
The methods suitable for preventing an iron frying pan from rusting include:
(a) Applying grease – Grease can act as a barrier to moisture and oxygen, which are necessary for the rusting process.
(b) Applying paint – Paint provides a protective coating that prevents exposure of the iron to moisture and oxygen.
(c) Applying a coating of zinc – This process, known as galvanization, not only provides a physical barrier but also offers sacrificial protection. Zinc is more reactive than iron and corrodes preferentially, thus protecting the iron.
(d) All of the above – Each of these methods can be effective in preventing rusting.
The correct answer is:
(d) All of the above.
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) calcium
(b) carbon
(c) silicon
(d) iron.
The description provided suggests that the element reacts with oxygen to form an oxide that has a high melting point and is also soluble in water. Generally, metals react with oxygen to form metallic oxides that can have high melting points and may be soluble in water, depending on the metal.
Looking at the options provided:
(a) Calcium (Ca) reacts with oxygen to form calcium oxide (CaO), which is a compound with a high melting point. Calcium oxide is also known to be soluble in water, and it forms calcium hydroxide (Ca(OH)$_2$), which is soluble in water.
(b) Carbon (C) reacts with oxygen to form carbon dioxide (CO$_2$) or carbon monoxide (CO), both gases at standard temperature and pressure, so they do not have a high melting point in the conventional sense nor are they "soluble" in water like ionic solids.
(c) Silicon (Si) reacts with oxygen to form silicon dioxide (SiO$_2$), also known as silica or quartz, which has a high melting point. However, silicon dioxide is not soluble in water; it's mostly insoluble and does not form a solution like ionic solids do.
(d) Iron (Fe) reacts with oxygen to form iron(III) oxide (Fe$_2$O$_3$) or iron(II) oxide (FeO), depending on the oxidation state of iron. While these oxides have relatively high melting points, they are not typically soluble in water.
Based on this information, the element that reacts with oxygen to give a compound with a high melting point and that is soluble in water is likely to be:
(a) calcium.
Food cans are coated with tin and not with zinc because
(a) zinc is costlier than tin.
(b) zinc has a higher melting point than tin.
(c) zinc is more reactive than tin.
(d) zinc is less reactive than tin.
Food cans are coated with tin and not with zinc because zinc is more reactive than tin. The reactivity of zinc might lead to the contamination of food, as zinc could potentially react with the acids or other substances in the food. Tin, being less reactive, serves as a safe coating to protect the food without reacting with it.
So the correct answer is:
(c) zinc is more reactive than tin.
You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
(a) To distinguish between samples of metals and non-metals using the given materials (hammer, battery, bulb, wires, and a switch), you can perform the following tests:
Conductivity Test:
Connect the wires to the battery, bulb, and switch to create a simple electrical circuit.
Place the material sample to be tested in the circuit as a part of the connection between the wires, preferably between the switch and the bulb.
Close the switch to complete the circuit.
Observe if the bulb lights up.
For metals:
The bulb will light up, indicating that the sample is a good conductor of electricity, which is a property of metals.
For non-metals:
The bulb will not light up, indicating that the sample is a poor conductor of electricity, which is typical for non-metals.
Malleability Test:
Strike the sample lightly with the hammer to see if it deforms without breaking.
Increase the force gradually and observe the behavior of the substance under stress.
For metals:
Metals are generally malleable, which means they can be hammered into thin sheets without shattering.
For non-metals:
Non-metals tend to be brittle and may break or shatter when struck with a hammer.
(b) Assessing the usefulness of these tests:
The conductivity test is very useful because most metals are excellent conductors of electricity, whereas most non-metals are poor conductors. This difference in electrical conductivity is a key characteristic that can be used to distinguish between metals and non-metals quite reliably. However, it's essential to exercise caution when dealing with electricity to avoid accidents.
The malleability test is also useful: since metals can be deformed under stress and retain their new shape without breaking, this property can differentiate them from non-metals, which are usually brittle and not malleable. However, this test can sometimes damage the samples and may not be suitable for all types of materials, especially those that are hard or may have some degree of both metal and non-metal properties (such as metalloids).
Both tests can provide a quick and relatively simple way to classify unknown samples as either metals or non-metals in many cases, but they are not without limitations. Some elements might exhibit properties that are not typical for their class, or the tests might not be conclusive for certain materials, such as those that are too hard to be struck with a hammer or too dangerous to be included in a simple electrical circuit. Additionally, these tests do not provide information about the specific type of metal or non-metal, and further testing could be required for a more detailed analysis.
What are amphoteric oxides? Give two examples of amphoteric oxides.
Amphoteric oxides are metal oxides that react with both acids and bases to produce salts and water . Two examples of amphoteric oxides are:
Aluminium oxide ($ Al_2O_3 $)
Zinc oxide ($ ZnO $) .
Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Metals that are above hydrogen in the activity series can displace hydrogen from dilute acids. For example, zinc (Zn) and iron (Fe) will displace hydrogen from dilute acids like hydrochloric acid (HCl) or sulfuric acid (H2SO4). These metals are known to be more reactive than hydrogen and will typically react with acids to produce a salt and hydrogen gas.
On the other hand, metals that are below hydrogen in the activity series will not displace hydrogen from dilute acids. Copper (Cu) and silver (Ag) are examples of metals which do not displace hydrogen from dilute acids as they are less reactive than hydrogen .
In the electrolytic refining of a metal $\mathrm{M}$, what would you take as the anode, the cathode and the electrolyte?
In the electrolytic refining process of a metal (designated here as $ \mathrm{M} $), the setup often involves the following components:
Anode: The anode is made up of the impure metal $ \mathrm{M} $ that needs to be refined. When a voltage is applied, the anode gradually dissolves, releasing metal ions into the electrolyte.
Cathode: The cathode is made of a strip of pure metal $ \mathrm{M} $. As the process takes place, metal ions from the electrolyte are reduced and deposited onto the cathode, increasing its thickness.
Electrolyte: The electrolyte is a suitable solution that facilitates the flow of ions and contains ions of the metal $ \mathrm{M} $. For the refining of metals such as copper, the electrolyte could be an aqueous solution of the salt of the metal, such as $ \mathrm{CuSO_4} $ for copper refining, often mixed with other substances like sulfuric acid to increase conductivity and allow for a better ion flow.
The pure metal gets deposited onto the cathode while the impurities either fall off and collect at the bottom of the electrolytic cell as sludge or stay in solution. This process results in the production of highly pure metal on the cathode.
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
(a) What will be the action of gas on
(i) dry litmus paper?
(ii) moist litmus paper?
(b) Write a balanced chemical equation for the reaction taking place.
(a) When sulphur is heated, it combines with oxygen from the air to form sulphur dioxide $\text{SO}_2$ gas. Sulphur dioxide is a colorless gas with a pungent, suffocating odor, and it is known for its acidic properties.
(i) The action of gas on dry litmus paper: $\text{SO}_2$ gas will not show any action on the dry litmus paper because it requires moisture to show its acidic properties.
(ii) The action of gas on moist litmus paper: When sulphur dioxide comes in contact with moisture, it forms sulfurous acid $\text{H}_2\text{SO}_3$. This sulfurous acid will turn blue litmus paper red due to its acidic nature.
(b) The balanced chemical equation for the reaction taking place when sulphur burns in air to form sulphur dioxide is:
$$ S(s) + O_2(g) \rightarrow SO_2(g) $$
However, because oxygen is diatomic, the balanced equation should include a coefficient to balance the number of oxygen atoms:
$$ S(s) + O_2(g) \rightarrow SO_2(g) $$
Given that sulphur and sulphur dioxide are both molecular entities, with no explicit charge and in their standard states (solid for sulfur, gas for sulfur dioxide), and $ O_2 $ is a diatomic molecule and also a gas, this is the correct balanced equation for the burning of sulphur in air.
State two ways to prevent the rusting of iron.
Two ways to prevent the rusting of iron are:
Galvanisation: This method involves coating steel and iron with a thin layer of zinc. Even if the zinc coating is broken, the galvanized article is protected against rusting.
Alloying: Making alloys is an effective method to improve the properties of a metal. For instance, when iron is mixed with a small amount of carbon, it becomes hard and strong. Stainless steel, an alloy of iron with nickel and chromium, is hard and does not rust .
What type of oxides are formed when non-metals combine with oxygen?
When non-metals combine with oxygen, they usually form acidic oxides. These oxides tend to react with water to form acids. For example, sulfur combines with oxygen to form sulfur dioxide $SO_2$, which further reacts with water to form sulfurous acid $H_2SO_3$, and carbon combines with oxygen to form carbon dioxide $CO_2$, which reacts with water to form carbonic acid $H_2CO_3$. These compounds generally increase the acidity of a solution when dissolved in water.
Give reasons
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
(a) Platinum, gold, and silver are used to make jewelry because they are very malleable and ductile, which means they can be shaped into intricate designs without breaking. They also have a lustrous appearance that does not tarnish easily, making them aesthetically appealing. Additionally, they are non-reactive and do not corrode or react with elements such as oxygen or sulfur easily, which ensures that jewelry made from these metals will retain its appearance over time.
(b) Sodium, potassium, and lithium are stored under oil because they are highly reactive metals, especially with water and oxygen. They can react vigorously and sometimes explosively with water, producing hydrogen gas and heat, which can be dangerous. Storing them under oil prevents them from coming into contact with moisture and oxygen in the air, minimizing the risk of a hazardous reaction.
(c) Although aluminium is a highly reactive metal, it is resistant to corrosion due to the formation of a thin layer of aluminium oxide on its surface when exposed to air. This layer protects the underlying metal from further oxidation, making it an ideal material for making cooking utensils. Moreover, aluminium is lightweight, has good thermal conductivity, and is not toxic, which makes it suitable for cooking food.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction because oxides are more easily reduced to the metal than carbonates or sulphides. Converting them to oxides removes the gaseous byproducts such as carbon dioxide or sulfur dioxide that would otherwise be released when reducing carbonates or sulphides. This helps simplify the extraction process and makes it more efficient, as the subsequent reduction process requires heating the metal oxide with a suitable reducing agent like carbon or carbon monoxide to yield the pure metal.
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Copper vessels tend to tarnish over time due to the reaction between copper and moisture present in the air, leading to the formation of copper oxide on the surface. This copper oxide is what gives the tarnished, dull brownish appearance to the vessels.
Sour substances like lemon or tamarind juice are effective in cleaning tarnished copper vessels because they contain citric acid (in lemon) and tartaric acid (in tamarind). These acids react with the copper oxide layer, dissolving it and leaving behind a shiny copper surface. The chemical reaction can be thought of as the acid reacting with the copper oxide to form a compound that is more easily washed away, restoring the vessel's natural sheen.
The reaction involved is: $$ \text{Copper oxide (CuO)} + \text{Acid} \rightarrow \text{Copper} + \text{Water} + \text{Salt} $$
For example, if we use citric acid from lemon juice, the reaction would be: $$ 2\text{CuO} + 2\text{H}_3\text{C}_6\text{H}_5\text{O}_7 \rightarrow 2\text{Cu} + 3\text{H}_2\text{O} + \text{C}_6\text{H}_5\text{O}_7\text{Cu}(OH)_2 $$
Thus, the cleaning process using lemon or tamarind juice is actually a chemical reaction where the acids help in removing the oxide layer from the copper vessels.
Differentiate between metal and non-metal on the basis of their chemical properties.
Metals and non-metals can be differentiated based on their chemical properties in the following ways:
Metals:
Metals can form positive ions by losing electrons to non-metals.
They combine with oxygen to form basic oxides. Some metals like aluminium and zinc form oxides that exhibit both basic and amphoteric properties.
Metals above hydrogen in the Activity series can displace hydrogen from dilute acids.
A more reactive metal can displace a less reactive metal from its salt solution.
Non-metals:
Non-metals form negatively charged ions by gaining electrons when reacting with metals.
The oxides that non-metals form are either acidic or neutral.
Non-metals do not displace hydrogen from dilute acids but react with hydrogen to form hydrides.
This differentiation emphasizes the propensity of metals to lose electrons and form basic oxides, whereas non-metals gain electrons and form acidic or neutral oxides. Additionally, the reactivity of metals with acids and their ability to participate in displacement reactions is a significant chemical characteristic of metals as opposed to non-metals.
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
The scenario described suggests that the so-called goldsmith used a solution containing an acid that could dissolve metals, likely aqua regia. Aqua regia is a mixture of hydrochloric acid (HCl) and nitric acid (HNO3) in a molar ratio of about 3:1, and it is one of the few substances that can dissolve gold.
When gold bangles are dipped in aqua regia, the gold reacts with the acids to form chloroauric acid and other byproducts. The chemical reaction that leads to the dissolution of gold in aqua regia is:
$$ \text{Au} + \text{3 HNO}_3 + \text{4 HCl} \rightarrow \text{AuCl}_4^- + \text{3 NO}_2 + \text{2 H}_2\text{O} + \text{3 H}^+ $$
The gold is converted into ions and goes into the solution, which would reduce the weight of the bangles. The sparkle observed could be due to the clean surface of the bangles after the removal of a thin layer of gold, exposing a fresh layer of gold underneath. This would give the appearance of the bangles being "restored" when, in reality, a small amount of gold has been removed, hence the reduced weight.
The lady's bangles lost weight because the gold was chemically dissolved into the solution. The fraudulent goldsmith likely intended to retrieve the dissolved gold from the solution later for personal gain.
Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
Copper is used to make hot water tanks rather than steel (an alloy of iron) for several reasons, including its superior corrosion resistance, thermal conductivity, and biofouling resistance:
Corrosion Resistance: Copper is naturally resistant to corrosion, which makes it a great material for hot water tanks as it can withstand the constant exposure to water without deteriorating. On the other hand, steel, which contains iron, can rust when exposed to water and oxygen over time, leading to leaks and contamination.
Thermal Conductivity: Copper is an excellent conductor of heat, which means that hot water tanks made of copper can heat water more efficiently, leading to faster and more consistent water heating. Steel has lower thermal conductivity in comparison, so it would not be as efficient in heating the water.
Biofouling Resistance: Copper has inherent antimicrobial properties, which helps in preventing the growth of bacteria, algae, and other microorganisms inside the tank. This is beneficial for maintaining water quality. Steel does not have such antimicrobial properties and might require additional treatments to prevent biofouling.
Durability: Copper tends to be a more ductile metal, this makes it less likely to suffer from the effects of thermal expansion and contraction which can weaken structural integrity over time. Steel, especially if not properly alloyed or treated, might be more susceptible to these changes and lead to a reduced lifespan of the tank.
Because of these properties, copper hot water tanks typically have a longer life expectancy and require less maintenance than those made from steel.
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Ask Chatterbot AIExtra Questions and Answers - Metals and Non-metals | NCERT | Science | Class 10
Assertion: In froth flotation process sodium ethyl xanthate is used as collector.
Reason: Sulphide ores are water soluble.
Option A) Both assertion and reason are correct and the reason is the correct explanation for the assertion.
Option B) Both assertion and reason are correct but the reason is not the correct explanation for the assertion.
Option C) Assertion is correct but the reason is wrong
Option D) Assertion is incorrect but the reason is correct
Assertion: In froth flotation process, sodium ethyl xanthate is indeed used as a collector. Sodium ethyl xanthate functions by adhering to the metal sulfides, increasing their hydrophobicity, which is crucial for their separation.
Reason: The statement that sulphide ores are water soluble is incorrect. In reality, most sulphide ores are not soluble in water, which is a significant reason why the froth flotation method is employed – to take advantage of the ores' lack of solubility and separate them using their differences in hydrophobic characteristics.
Given the above analysis:
The Assertion is correct
The Reason is incorrect
Thus, the correct answer is:
Option C) Assertion is correct but the reason is wrong
State the characteristics of groups in the periodic table.
Groups in the periodic table are the vertical columns that run from top to bottom. There are a total of 18 groups.
Here are the key characteristics of the elements within these groups:
Similar properties are observed among elements in the same group, primarily because they have similar outer electronic configurations.
There is a gradual change in properties as you move down a group. This is due to the decreasing attraction between the nucleus and the valence electrons.
Elements in a group share the same valency, which contributes to their chemical reactions.
Identical chemical properties are found among the elements within the same group, reinforcing their ability to undergo similar reactions.
Physical properties, such as melting point, boiling point, and density, show a gradual variation across the group.
Which among the given is formed when zinc reacts with dilute nitric acid?
A. Hydrogen gas
B. Nitrous oxide
C. Nitric oxide
D. Nitrogen dioxide
Correct Option: B. Nitrous oxide
When zinc reacts with dilute nitric acid, the reaction typically yields zinc nitrate, water, and nitrous oxide as products. The reaction varies depending on factors like the metal's nature and the acid's concentration. The balanced chemical equation for this reaction is: $$ 4 \mathrm{Zn} + 10 \mathrm{HNO}_3 \rightarrow 4 \mathrm{Zn(NO}_3)_2 + 5 \mathrm{H}_2\mathrm{O} + \mathrm{N}_2\mathrm{O} $$ Thus, the gas evolved when zinc reacts with dilute nitric acid is nitrous oxide (N$_2$O).
Categorize the following substances as Metals and Non-metals: Graphite, Zinc, Diamond, Oxygen, Sodium, Aluminium, Silver, Carbon, Mercury, Phosphorus
Metals:
Zinc
Sodium
Aluminium
Silver
Mercury
Non-metals:
Graphite
Diamond
Carbon
Oxygen
Phosphorus
Assertion: Sodium metal reacts violently with water and burns with a yellow flame. Reason: A large amount of heat is generated and hydrogen evolved immediately catches fire.
A. Assertion: False, Reason: False
B. Assertion: True, Reason: True, Reason is not the correct explanation of assertion
C. Assertion: True, Reason: True, Reason is the correct explanation of assertion
D. Assertion: True, Reason: False
The correct option is C
Assertion: True
Reason: True
The reason is the correct explanation for the assertion.
Sodium metal reacts violently with water, producing sodium hydroxide and hydrogen gas as shown in the reaction: $$ 2 \text{Na(s)} + \text{H}_2 \text{O(l)} \rightarrow 2 \text{NaOH(aq)} + \text{H}_2 \text{(g)} $$
This reaction is exothermic, generating sufficient heat that exceeds the self-ignition temperature of hydrogen gas. As a result, the hydrogen gas catches fire immediately and burns with a yellow flame, augmented by the presence of sodium metal vapors. Consequently, both the assertion and reason are true, and the reason correctly explains the assertion.
The property of virtue of which metals can be drawn into wire is known as:
A. malleability.
B. ductility.
C. sonorous nature.
D. conductivity.
The correct answer is Option B: Ductility.
Ductility refers to the property of metals that allows them to be stretched into wires without breaking.
Which of the following helps to prevent the leaching of heavy metals?
A) Thiobacilli
B) Actinoplanes
C) Ideonella sakaiensis
D) Sulphobacilli
The correct options are:
A) Thiobacilli
D) Sulphobacilli
Both Thiobacilli and Sulphobacilli help prevent the leaching of heavy metals. These bacteria convert heavy metals into less harmful compounds, thereby preventing them from dissolving and seeping into the ground. This conversion reduces the mobility and toxicity of the metals, effectively mitigating environmental contamination.
Which of the following metals is reacted with iron oxide in the thermite process?
A. $\mathrm{Cu}$
B. $\mathrm{Co}$
C. $\mathrm{Al}$
D. $\mathrm{Na}$
The correct answer is Option C: $\mathrm{Al}$ (Aluminum).
In the thermite reaction, aluminum ($\mathrm{Al}$) is used to reduce iron oxide ($\mathrm{Fe}_{2} \mathrm{O}_{3}$). This process is commonly employed for welding railway tracks or repairing broken machine parts.
The chemical equation for the thermite reaction is:
$$ \mathrm{Fe}{2} \mathrm{O}{3}(\mathrm{s}) + 2 \mathrm{Al}(\mathrm{s}) \rightarrow 2 \mathrm{Fe}(\mathrm{l}) + \mathrm{Al}{2} \mathrm{O}{3}(\mathrm{s}) + \text{Heat} $$
This is a displacement reaction and is highly exothermic. The reaction generates enough heat to melt the iron produced, demonstrating the intensity of heat evolved during the process.
Soft iron is preferred over steel in making electromagnets because of permeability and retentivity.
A high
B zero
C zero
D low
The correct options are:
A high
D low
Soft iron is more suitable than steel for creating electromagnets primarily due to two of its magnetic properties:
High permeability: This allows the soft iron to be easily magnetized even in the presence of a weak magnetizing field.
Low retentivity: This property ensures that the soft iron does not retain magnetic properties once the magnetizing field is removed.
What is Raney nickel?
Raney nickel is a highly effective catalyst constructed from tiny grains of a nickel-aluminium alloy. Initially developed by American engineer Murray Raney in 1926, it was primarily used for the hydrogenation of vegetable oils. Today, it is popularly used as a heterogeneous catalyst in various organic syntheses, especially in hydrogenation reactions.
The production of Raney nickel involves treating a block of nickel-aluminium alloy with concentrated sodium hydroxide through a process known as "activation". This treatment primarily dissolves the aluminium, leaving behind a porous structure with a significantly large surface area, which enhances its catalytic activity. Typically, the catalyst contains about 85-percent nickel by mass, approximately corresponding to two atoms of nickel for every atom of aluminium. The residual aluminium serves to maintain the integrity of the catalyst’s porous structure.
It’s important to note that "Raney" is a registered trademark of W.R. Grace and Company. Thus, only products from its Grace Davison division may accurately be labelled as "Raney nickel". The terms "skeletal catalyst" or "sponge-metal catalyst" are more generic and can be used to denote catalysts with similar physical and chemical characteristics as Raney nickel.
You are given a hammer, a battery, a bulb, wires, and a switch.
(a) How could you use them to distinguish between samples of metals and nonmetals?
(a) By utilizing the hammer, you can test the malleability of each sample. If a sample can be beaten into thin sheets, it indicates that it is malleable and hence, a metal; if it cannot, it's a non-metal. To further distinguish between metals and non-metals, you can assemble the battery, bulb, wires, and switch to create a basic circuit. Include the sample within this circuit. If the bulb lights up, indicating that electricity is passing through the sample, it is conclusive that the sample conducts electricity and is therefore a metal. If the bulb remains off, the sample is a non-metal due to its inability to conduct electricity.
An element $X$ from group 2 of the periodic table reacts with an element $Y$ from group 17 to form a compound.
(a) What is the nature of the compound formed?
(b) State whether the compound formed will conduct electricity or not.
(c) Give the formula of the compound formed.
(d) What is the valency of element X?
(e) How many electrons are there in the outermost shell of an atom of element $Y$?
(a) The compound formed is ionic in nature. This is because elements from Group 2 are metals which tend to lose electrons, and those from Group 17 are non-metals which tend to gain electrons. The transfer of electrons from metals to non-metals leads to the formation of an ionic bond.
(b) Yes, the compound will conduct electricity. This is because the compound is ionic and ionic compounds can conduct electricity when molten or dissolved in water as they contain mobile ions.
(c) Since element $X$ falls under Group 2, it has a valency of 2. Element $Y$, being from Group 17, has a valency of 1. Therefore, one atom of $X$ will combine with two atoms of $Y$ to form the compound $XY_2$.
(d) The valency of element $X$ is 2. This is characteristic of elements in Group 2, which lose two electrons to achieve a stable configuration.
(e) Element $Y$ from Group 17 has seven electrons in the outermost shell. This can be calculated from the group number by using the formula: $$ \text{No. of valence electrons} = \text{Group number} - 10 = 17 - 10 = 7. $$
Which of the following will not conduct electricity?
A. Molten $\mathrm{NaCl}$
B. $\mathrm{NaCl}$ dissolved in water
C. Solid $\mathrm{NaCl}$
D. Both molten and solid $\mathrm{NaCl}$
The correct answer is C: Solid $\mathrm{NaCl}$.
Solid $\mathrm{NaCl}$ does not conduct electricity due to the absence of free moving ions within its lattice structure. In the solid state, the ions are fixed in place and cannot move freely to conduct electrical current. This is contrasted with molten $\mathrm{NaCl}$ and $\mathrm{NaCl}$ dissolved in water, where the ions are free to move and can thus carry an electric current.
What is obtained when a metal oxide of the highly reactive metals react with water?
A. metal oxide + water
B. metal hydroxide + heat energy
C. metal hydroxide
D. metal oxide
The correct answer to the question is Option B: metal hydroxide + heat energy. When a metal oxide from highly reactive metals reacts with water, the chemical reaction typically produces a metal hydroxide and releases heat energy.
For instance, the reaction can be represented as: $$ \text{Na}_2\text{O} + \text{H}_2\text{O} \rightarrow 2 \text{NaOH} + \text{heat} $$
This shows the formation of sodium hydroxide (NaOH) and the release of heat during the reaction with water.
How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal?
When hydrochloric acid reacts with an active metal like calcium (Ca), the resulting chemical reaction can be represented as:
$$ \text{Ca} + 2\text{HCl} \to \text{CaCl}_2 + \text{H}_2 $$
In this equation, $ \text{Ca} $ is calcium, $ \text{HCl} $ is hydrochloric acid, $ \text{CaCl}_2 $ is calcium chloride, and $ \text{H}_2 $ is hydrogen gas. As shown, hydrogen gas is evolved during the reaction.
To test for the presence of hydrogen gas that is liberated, you can perform the following test:
Test for the Presence of Hydrogen Gas:
As hydrogen gas is liberated, collect it by holding a test tube or other container over the reaction site.
Take a burning splinter and carefully bring it to the mouth of the test tube.
If hydrogen gas is present, it will burn with a characteristic pop sound.
This test is based on the fact that hydrogen is flammable and burns with a pop sound when ignited. This property is unique to hydrogen gas among common gases typically encountered in laboratories, making this test a good confirmation of its presence.
Report on extraction of metals of low reactivity: silver, platinum, and gold.
SILVER Extraction
Silver is primarily extracted from the ore argentite ($\text{Ag}_2S$). The common method employed for the extraction of silver is known as the cyanide process, which utilizes sodium cyanide solution. Initially, the ore is crushed and concentrated, then treated with this solution. This chemical interaction produces sodium argento cyanide ($\text{Na}[\text{Ag}(\text{CN})_2]$):
$$ \text{Ag}_2S + 4\text{NaCN} \rightarrow 2\text{Na}[\text{Ag}(\text{CN})_2] + \text{Na}_2S $$
Further, this solution reacts with zinc dust to result in the formation of sodium tetra cyanozicate and precipitated silver. The precipitated form is often referred to as spongy silver:
$$ \text{Zn} + 2\text{Na}[\text{Ag}(\text{CN})_2] \rightarrow \text{Na}_2[\text{Zn}(\text{CN})_4] + 2\text{Ag} $$
The spongy silver then undergoes fusion with potassium nitrate to enhance its purity. Lastly, the silver obtained is further purified using the electrolytic process.
GOLD Extraction
Gold extraction varies depending on the origin and composition of the ores. This may entail several processes ranging from simple panning and sluicing (retrieving small nuggets and flakes directly) within placer mining contexts to more intensive hydrometallurgical and pyrometallurgical processes reliant on modern equipment and sophisticated techniques.
Hydraulic mining, which employs high-pressure jets of water, was prominently used during the Californian gold rush to break down placer ores. For hard rock gold ores, predominant commercial extraction post mid-20th century has involved open pit or subsurface mining methods.
Post-mining, the ore is typically treated as a whole using dump or heap leaching processes if they are low-grade, oxide deposits. For higher grade or cyanide-leaching-resistant ores, elaborate processing including grinding, concentration, roasting, and pressure oxidation prior to cyanidation is necessary.
PLATINUM Extraction
Platinum, being an extremely rare metal, sees varying methods of extraction based on the available technological resources. Typically extracted from intricate ores, it demands precise and controlled processing to obtain in viable quantities.
Initially, platinum ore undergoes crushing to produce tiny particles conducive for further treatment. These particles are then processed in an aeration tank where air bubbles are introduced to adhere to the platinum particles, allowing them to rise to the surface. The layer formed at the top can then be skimmed off and refined further to obtain pure platinum.
These processes underscore the significant complexities and technological requirements integral to metal extraction from ores of low reactivity such as silver, gold, and platinum.
What changes in the color of iron nails and copper sulphate solution do you observe after keeping the iron nails dipped in copper sulphate solution for about 30 minutes?
When an iron nail (Fe) is kept in a copper sulfate ($\mathrm{CuSO}_4$) solution, a chemical reaction occurs due to iron being more reactive than copper. The reaction, which involves iron displacing copper from the copper sulfate, can be represented by the following equation: $$ \mathrm{Fe} + \mathrm{CuSO}_4 \rightarrow \mathrm{FeSO}_4 + \mathrm{Cu} $$
Originally, the copper sulfate solution is blue in color. However, as the reaction progresses, it produces iron(II) sulfate ($\mathrm{FeSO}_4$), which has a light green color. As a result, you will observe the color of the solution changing from blue to light green. Additionally, there will be a deposition of copper on the surface of the iron nail, which can be seen as a reddish-brown layer.
The electronic configurations of atoms of three elements A, B, and C are $(2,8,1)$, $(2,8,6)$, and $(2,8,18,7)$ respectively.
Which option classifies the elements A, B, and C as metals and non-metals correctly?
A) A -> Non-Metal, B -> Non-Metal, C -> Non-Metal
B) A -> Metal, B -> Metal, C -> Metal
C) A -> Metal, B -> Non-Metal, C -> Non-Metal
D) A -> Metal, B -> Metal, C -> Non-Metal
The correct classification of elements A, B, and C, based on their electronic configurations and general properties of metals and non-metals, is given in option C:
A -> Metal, B -> Non-Metal, C -> Non-Metal
Explanation:
Element A has the electronic configuration $(2, 8, 1)$. It has one electron in its outermost shell, which suggest it is likely to lose an electron easily to achieve a stable noble gas configuration of $(2, 8)$. This property is characteristic of metals.
Element B has the electronic configuration $(2, 8, 6)$. With six electrons in the outer shell, it is more inclined to gain or share two electrons to complete its octet $(2, 8, 8)$, aligning with properties typical of non-metals.
Element C has the electronic configuration $(2, 8, 18, 7)$. Similar to Element B, having seven electrons in the outermost shell suggests a tendency to gain or share one electron to complete its octet, a trait associated with non-metals.
Hence, option C is the correct choice: A -> Metal, B -> Non-Metal, C -> Non-Metal.
The metal always found in free state is
A) Copper
B) Gold
C) Silver
D) Sodium
The correct answer is B) Gold.
Gold is often found in the native state, which means it can be found in its natural, metallic form and not combined with other elements. This makes gold one of the noble metals that does not generally react with other substances. Unlike gold, metals like copper, silver, and sodium are usually found combined with other elements in the Earth's crust.
When hydrogen is passed over a black solid compound A, the products are 'a colourless liquid' and 'a reddish brown metal B.'
Substance B is divided into two parts, each placed in separate test tubes.
Dilute HCl is added to one part of substance B and dilute HNO3 to the other.
(a) Name the substances A and B.
(b) Give two tests for the colorless liquid formed in the experiment.
(c) What happens to substance A when it reacts with hydrogen? Give reasons for your answer.
(d) Write an equation for the reaction between hydrogen and substance A.
(e) Is there any reaction between substance B and dilute hydrochloric acid? Give reasons for your answer.
(a) The substances involved are as follows:
Substance A is CuO (Copper(II) oxide).
Substance B is Cu (Copper).
(b) Two tests for identifying the colorless liquid (water) formed in the reaction:
Litmus Test: The colorless liquid does not change the color of litmus paper, indicating it is neutral.
Anhydrous Copper (II) Sulphate Test: When mixed with anhydrous copper(II) sulfate, which is white in color, the liquid turns it blue. This confirms the presence of water.
(c) When hydrogen gas is passed over CuO (substance A), a reduction reaction occurs:
CuO loses oxygen to form copper metal (Cu), and therefore, it is reduced.
This reaction illustrates a typical reduction process where hydrogen acts as a reducing agent.
(d) The balanced chemical equation for the reaction between hydrogen and copper(II) oxide is: $$ \text{CuO} + H_2 \rightarrow \text{Cu} + H_2O $$
(e) There is no reaction between substance B (Cu - copper) and dilute hydrochloric acid (HCl) because:
Copper is less reactive than hydrogen and does not displace hydrogen from dilute acids.
Chemical Equation illustrating the lack of reaction between copper and dilute HCl: $$ \text{Cu} + \text{HCl} \rightarrow \text{No reaction} $$
Which of the following pairs do not show the inert-pair effect?
A Tl and Pb
B Sn and Bi
C Sn and Pb
D Si and Ge
The correct answer is Option D: Si and Ge. The Inert Pair Effect is typically observed in elements from the 13th to the 15th groups of the periodic table, particularly in elements from the 5th and 6th periods due to the impact of lanthanide contraction.
This effect is notable in elements like Tl, Pb, and Sn, leading to a greater stability in their lower oxidation states compared to their higher ones. These elements are positioned lower in their respective groups on the periodic table.
In contrast, Si and Ge do not exhibit the inert pair effect as they are located higher in the periodic table. Therefore, Option D, which pairs Si and Ge, is the correct choice as these elements do not show the inert pair effect.
Nitrogen is a
A. Halogen
B. Noble Gas
C. Nonmetal
D. Alkaline Earth
The correct answer is C. Nonmetal
Nitrogen is classified as a nonmetal. This category of elements typically includes substances that are poor conductors of heat and electricity, often exist in gaseous states like nitrogen itself, and exhibit relatively high ionization energies and electronegativities.
How are meteors different from meteorites?
The terms meteor and meteorite refer to different stages of a space object's interaction with Earth. Here's how they differ:
Meteors: These are small space objects that enter the Earth's atmosphere. They are often pieces of comet or asteroid debris.
When these objects enter the Earth's atmosphere, they travel at very high speeds, leading to intense friction with the atmospheric gases. This friction heats the object so much that it glows brightly, commonly appearing as a streak of light in the sky.
Meteorites: These are the remnants of meteors that survive their passage through the atmosphere and reach the Earth's surface. Most meteors burn up completely in the atmosphere due to the heat, but those that do make it to the ground are called meteorites. This difference in terminologies primarily arises from whether the object disintegrates in the atmosphere or survives to make an impact on the surface.
Which is a non-metal that can conduct electricity?
A Sodium
B Copper
C Graphite
D Iron
The correct answer is C) Graphite.
Graphite is an allotrope of carbon, which is classified as a non-metal. Its structure comprises hexagonal arrays where each carbon atom is covalently bonded to three others. The presence of a free electron in the structure due to each carbon atom only bonding with three others allows for electron mobility. This mobility of the free electron enables graphite to conduct electricity effectively, distinguishing it from most other non-metals.
In contrast, Sodium, Copper, and Iron are all metals known for their conductivity, primarily due to the abundance of free electrons, but they do not fulfill the requirement of being a non-metal that can conduct electricity as asked in the question.
Classify the following as good conductors and insulators:
Wood, plastic, copper, rubber, silver, iron, glass, steel, distilled water, tap water, sea water.
Good conductors and insulators have distinct characteristics when it comes to their ability to conduct electricity. In the provided list:
Good Conductors:
Copper: Known for its excellent electrical conductivity.
Silver: Has the highest electrical conductivity of all metals.
Iron: A moderate conductor of electricity.
Steel: An alloy mainly consisting of iron and carbon, conducts electricity well.
Tap Water: Contains minerals and impurities that facilitate electrical conduction.
Sea Water: High in salt content, making it a very good conductor of electricity.
Good Insulators:
Wood: Generally a poor conductor of electricity.
Plastic: Widely used for its insulating properties.
Rubber: Especially used in insulating electrical wires and components.
Glass: Very poor conductor; often used as an insulator in electrical applications.
Distilled Water: Lacks ions, making it a poor conductor of electricity.
State the major difference between the composition of steel and stainless steel. Why is stainless steel considered better than steel?
Steel is primarily composed of iron and carbon. This combination is also referred to as plain carbon steel or mild steel, which tends to have a higher carbon content with a low melting point.
In contrast, stainless steel is distinguished by its significant chromium content, which typically starts at 10.5%. This chromium forms an invisible layer on the steel's surface, which prevents staining and corrosion.
To further delve into their compositions:
Carbon Steel: Contains iron and carbon ranging from 0.12% to 2.00%. This category may also encompass alloy steels, potentially having up to 10.5% alloy content. Even within this range, the properties, particularly the hardness, can vary significantly.
Stainless Steel: Comprised of iron, carbon, and at least 10.5% chromium. The chromium is critical as it reacts with oxygen to create a passive, protective layer that shields the steel from corrosion.
Key difference: The primary distinction lies in stainless steel's addition of chromium, nickel, nitrogen, and sometimes molybdenum, which enhance its corrosion resistance.
Why is stainless steel considered better?Stainless steel is favored for its ability to resist corrosion effectively compared to plain steel. This makes it ideal for environments exposed to moisture or chemicals where ordinary steel would corrode and degrade. Thus, stainless steel's superior corrosion resistance makes it more suitable for a wide range of applications, especially in wet and corrosive environments.
Identify a non-metal that turns into a flame when exposed to air.
A) Gold
B) Sodium
C) Phosphorus
D) Sulphur
The correct answer is C) Phosphorus.
Phosphorus is a non-metal that ignites and burns when exposed to air, displaying its highly reactive nature. To prevent it from catching fire, phosphorus is typically stored underwater, where it is stable because non-metals generally do not react with water.
Name a metal that replaces silver from a silver nitrate solution.
Copper is a metal that can replace silver from a silver nitrate solution.
"Name the material used for making a fuse wire and give a reason."
Fuse wire is typically made from an alloy of lead and tin. This choice is due to the high resistivity and low melting point of the alloy, which are ideal properties for a material that needs to melt under excessive electrical current to protect electrical circuits.
Methane gives water gas when heated with steam in the presence of
A) $\mathrm{Cu}$
B) $\mathrm{Ni}$
C) $\mathrm{Zn}$
D) $\mathrm{Al}$
The correct answer is B) Ni.
Water gas is primarily composed of carbon monoxide (CO) and hydrogen (H$_2$). This mixture is produced when methane ($\mathrm{CH}_4$) is treated with steam at high temperatures, specifically around $1273 \mathrm{~K}$, in the presence of a Nickel (Ni) catalyst. The reaction can be represented by the following equation: $$ \mathrm{CH}_4 + \mathrm{H}_2\mathrm{O(g)} \xrightarrow{\mathrm{Ni}} \mathrm{CO} + 3\mathrm{H}_2 $$
It is important to note that the CO produced is extremely toxic. This is because it forms a stable complex with hemoglobin in the blood, which significantly diminishes the blood's oxygen-carrying capacity.
The ratio of the molar amounts of $\mathrm{H}_{2}\mathrm{S}$ needed to precipitate the metal ions from $20 \mathrm{mL}$ each of $1 ~\mathrm{M}~ \mathrm{Cd}\left(\mathrm{NO}_{3}\right){2}$ and $0.5 ~\mathrm{M ~CuSO}_{4}$ is
(A) $1:1$
(B) $2:1$
(C) $1:2$
(D) Indefinite
To solve the problem, we need to determine how many moles of $\mathrm{H}_2\mathrm{S}$ are required to precipitate metal ions from solutions of $\mathrm{Cd(NO}_3\mathrm{)_2}$ and $\mathrm{CuSO}_4$.
Chemical reaction for precipitation of Cadmium as Cadmium Sulfide: $$ \mathrm{Cd}^{2+} + \mathrm{S}^{2-} \rightarrow \mathrm{CdS} $$ Each mole of $\mathrm{Cd}^{2+}$ requires 1 mole of $\mathrm{S}^{2-}$ to form $\mathrm{CdS}$.
Calculating moles of $\mathrm{Cd}^{2+}$ in the given solution:
Molarity of $\mathrm{Cd(NO}_3\mathrm{)_2}$ is $1 \mathrm{M}$.
Volume of solution = $20 \mathrm{mL}$ = $0.020 \mathrm{L}$.
Moles of $\mathrm{Cd}^{2+}$ = Molarity × Volume = $1 \times 0.020 = 0.020 \mathrm{moles}$.
Chemical reaction for precipitation of Copper as Copper Sulfide: $$ \mathrm{Cu}^{2+} + \mathrm{S}^{2-} \rightarrow \mathrm{CuS} $$ Each mole of $\mathrm{Cu}^{2+}$ requires 1 mole of $\mathrm{S}^{2-}$ to form $\mathrm{CuS}$.
Calculating moles of $\mathrm{Cu}^{2+}$ in the given solution:
Molarity of $\mathrm{CuSO}_4$ is $0.5 \mathrm{M}$.
Volume of solution remains $20 \mathrm{mL}$ = $0.020 \mathrm{L}$.
Moles of $\mathrm{Cu}^{2+}$ = Molarity × Volume = $0.5 \times 0.020 = 0.010 \mathrm{moles}$.
Ratio of $\mathrm{H}_2\mathrm{S}$ required:
Moles of $\mathrm{H}_2\mathrm{S}$ needed for $\mathrm{CdS}$: $0.020 \mathrm{moles}$ (as each mole of $\mathrm{Cd}^{2+}$ requires an equivalent mole of $\mathrm{S}^{2-}$).
Moles of $\mathrm{H}_2\mathrm{S}$ needed for $\mathrm{CuS}$: $0.010 \mathrm{moles}$ (as each mole of $\mathrm{Cu}^{2+}$ requires an equivalent mole of $\mathrm{S}^{2-}$).
Thus, the ratio is given by: $$ \text{Ratio} = \frac{0.020}{0.010} = 2:1 $$
Answer: The correct option is (B) $2:1$. This means that twice as much $\mathrm{H}_2\mathrm{S}$ is required for precipitating $\mathrm{Cd}^{2+}$ compared to $\mathrm{Cu}^{2+}$.
A metal is present in plants, bones, egg shells, and sea shells. It is also used to remove oxygen from molten steel. The metal is
A $\mathrm{Al}$
B $\mathrm{Ca}$
C $\mathrm{Mg}$
D $\mathrm{Na}$
The correct option is B, which is $\mathbf{Ca}$ (Calcium).
Calcium ($\mathrm{Ca}$) is inherently present in various biological materials such as plants, bones, egg shells, and sea shells. It plays a crucial role in the industry by acting as an oxygen scavenger from molten steel.
The chemical reaction involving the removal of oxygen can be represented by the equation: $$ 2 \mathrm{Ca} + \mathrm{O}_{2} \rightarrow 2 \mathrm{CaO} $$
In this reaction, calcium combines with oxygen to form calcium oxide ($\mathrm{CaO}$), effectively purifying the steel by removing oxygen.
Assertion: Copper reacts with hydrochloric acid and liberates hydrogen from the solution of dilute hydrochloric acid.
Reason: Hydrogen is present below copper in the electrochemical series.
A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but the reason is not the correct explanation of the assertion.
C) If the assertion is true but the reason is false.
D) If the assertion and reason are both false.
The correct option is D - If the assertion and reason are both false.
Assertion is false: Copper does not react with hydrochloric acid to liberate hydrogen gas. Copper is located below hydrogen in the electrochemical series, indicating that it cannot displace hydrogen from its acid (HCl).
Reason is false: The statement that hydrogen is present below copper in the electrochemical series is incorrect. In fact, hydrogen is above copper in the electrochemical series, further confirming why copper cannot displace hydrogen from hydrochloric acid.
Observe the table and identify metals and non-metals. Select the correct option.
S. No. | Set 1 | Set 2 |
---|---|---|
1) | Sodium (Na) | Oxygen (O) |
2) | Magnesium (Mg) | Chlorine (Cl) |
3) | Iron (Fe) | Helium (He) |
4) | Gold (Au) | Sulphur (S) |
5) | Calcium (Ca) | Carbon (C) |
A) Set 1: metals and set 2: non-metals.
B) Set 1: non-metals and set 2: metals.
C) Both sets 1 & 2 are metals.
D) Both sets 1 & 2 are non-metals.
The correct answer is Option A: Set 1: metals and set 2: non-metals.
Metals generally exhibit properties such as being solid at room temperature (except for mercury), having high melting points, and being good conductors of heat and electricity. They are also malleable, ductile, and sonorous.
In contrast, most non-metals can be found in solid or gaseous states (bromine being a liquid exception) and typically do not conduct heat and electricity well.
From the observed table:
Set 1 includes:
Sodium (Na)
Magnesium (Mg)
Iron (Fe)
Gold (Au)
Calcium (Ca) These elements are all metals.
Set 2 includes:
Oxygen (O)
Chlorine (Cl)
Helium (He)
Sulphur (S)
Carbon (C) These elements are all non-metals.
Metalloids are elements that have properties of metals.
A) True
B) False
The correct answer is B) False.
Metalloids are elements that exhibit properties of both metals and non-metals. They are typically positioned in a zig-zag line on the periodic table, between group 13 and group 17. This placement reflects their hybrid characteristics.
Aluminium and copper metals are used in making electrical wires because:
They are good conductors of electricity and they are ductile.
They are ductile.
They are good conductors of heat.
They are good conductors of electricity.
The correct option is A: They are good conductors of electricity and they are ductile.
Aluminium and copper metals are chosen for making electrical wires because they possess two essential properties:
Good conductivity: They are excellent conductors of electricity.
Ductility: They can be drawn into thin wires without breaking.
During galvanisation, iron metal is given a thin coating of one of the following metals. This metal is:
(a) chromium, (b) tin, (c) zinc, or (d) copper.
The correct answer is (c) zinc.
Galvanisation is a process where iron objects are dipped into molten zinc. This procedure results in a thin zinc coating on the iron, which serves to protect it from corrosion. Zinc, due to its high reactivity, forms a layer of zinc oxide, preventing the iron from being exposed to atmospheric air, thereby inhibiting rust formation.
______ is used as a catalyst which is fitted in the automobiles to reduce emission of poisonous gases.
Option 1: Platinum Option 2: Silicon Option 3: Neon
Correct Option: 1: Platinum
To mitigate air pollution, modern automobiles incorporate a device known as a catalytic converter. This device helps to lower the emissions found in car exhaust by facilitating redox reactions (reduction-oxidation reactions). Catalytic converters typically use metals such as platinum, palladium, and rhodium as catalysts to effectively reduce the emission of toxic gases.
An alkali metal M reacts with to form metal oxide. The metal oxide formed is basic in nature.
A. hydrogen
B. oxygen
C. basic
D. acidic
E. amphoteric
The correct options are:
B) Oxygen
C) Basic
Explanation:Alkali metals react with oxygen gas to form metal oxides. These metal oxides, when dissolved in water, form bases. Therefore, these oxides are considered basic oxides.
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Ask Chatterbot AIUses and Applications of Non-Metals - Metals and Non-metals | Class 10 NCERT | Science
Non-metals, known for their poor conductivity, are primarily used as insulators against electrical current. These substances are abundant in Earth's atmosphere, as they are composed of non-metallic elements. Their electron bonds can be broken down by lightning, causing large voltages to be discharged to the ground.
Chemical elements can be divided into metals, non-metals and metalloids based on their ability to conduct electricity at ambient temperatures and pressures. However, other distinguishing factors are taken into account in the periodic table. Even though noble gases and halogens are non-metal in nature, they have unique properties that result in their special classification.
By studying the physics, chemistry, and geology of non-metals, we gain insights into how these elements are synthesized in the universe, which then influences their uses.
Uses of Non-Metals in Daily Life:
Nitrogen: Approximately 78% of the atmosphere by volume is nitrogen, an important industrial component for making ammonia, a key ingredient in fertilizers.
Oxygen: Vital for respiration, oxygen also performs crucial roles in industrial processes, such as steel manufacturing and metal fabrication that require high temperatures. Oxygen cylinders are used in emergency situations and hospitals for trauma care.
Noble Gases: Gasses like argon and xenon are used in eye-catching illuminated displays for advertisements.
Helium: Widely used in scientific research for generating specific environments. It is also used by meteorology departments for weather balloons, and in light bulbs filled with neon, argon, krypton to produce laser beams.
Chlorine and Iodine: These elements are used in water purification and as antiseptics for wound treatment, respectively. Chlorine also has applications as a bleaching agent in stain removal and in the manufacture of chemicals and PVC, while Iodine is used to prevent throat infections.
Usage of Non-Metals in Ancient Times:
Traditionally, non-metals didn't permeate daily life significantly until the 18th Century. Exceptions were carbon and sulfur, known for their association with fire, which facilitated immense contributions in early human settlements. Carbon was familiar in the form of charcoal and lamp black, used in making ink for writing. Sulfur was closely related to volcanic zones and known for its distinct yellow color and the blue flame it produced when burnt. Lesser known non-metals like phosphorus were used for fire displays.
Common Uses of Non-Metals:
Carbon: Utilized in the manufacture of rubber tyres, black printing ink, and iron manufacturing. Forms of carbon like graphite are used in lubricating agents and electromagnet instruments.
Industrial Diamond: They are used for cutting glass and other precision instruments.
Daily use articles: Non-metals form a large part of everyday items, such as pens, erasers, pencils, plastic materials, PVC pipes, medicines, and drugs, fuelling vehicles.
Ten Uses of Non-Metals:
Diamond: Used in industrial cutting tools, grinding stones, turntable needles, and glass-cutting knives.
Graphite: Used in pencils which can be cut/sliced easily.
Charcoal: Used for small fires or ultra-filtration in water filters and sugar industry for decolourisation purposes.
Charged Charcoal: Used as a bad odour absorbent in refrigerators.
Activated Charcoal: Used as a purifier in industrial processes.
Carbon Polymers: Used in synthetic fibre productions.
Chlorine: Main ingredient for bleach, used in cleaning and purifying water.
Iodine: Used to make tincture iodine for the pharmaceutical industry.
Sulphur: Used in firecrackers.
Carbon, Hydrogen, Oxygen: Main ingredients of all our organic compounds.
Electron Affinities of Non-Metals
Non-metals typically have high electron affinities due to their strong tendency to acquire additional electrons to obtain a full valence shell. Note that electron affinity refers to an atom's capability of accepting an electron and it is defined as the amount of energy released when an electron is added to an atom or molecule. Here are some key non-metal elements and their characteristic electron affinities:
Oxygen (O): Oxygen has a high electron affinity at about 140.97 kJ/mol. It readily accepts additional electrons since it only needs two more to complete its valence shell.
Nitrogen (N): Nitrogen has significantly lower electron affinity than oxygen, only about 7.00 kJ/mol, due to the half-filled state of its p-orbitals, which proves stable.
Chlorine (Cl): Among non-metals, Chlorine takes precedence with one of the highest electron affinities, approximately 349 kJ/mol. This propensity stems from its need for only one additional electron to complete its outer electron shell.
Sulfur (S): Sulfur, with an electron affinity of about 200 kJ/mol, has a strong inclination to accept additional electrons to achieve 8 electrons in its outer shell for stability.
Carbon (C): Carbon has a comparatively lower electron affinity, approximately 121.75 kJ/mol, due to the stability of its half-filled p-orbital.
Phosphorus (P): Phosphorus has an electron affinity of about 72 kJ/mol making it relatively less inclined towards accepting an extra electron because it has 5 electrons in its outer shell, giving it a relatively stable half-filled p-orbital.
In general, non-metals exhibit the tendency to gain electrons due to their high electron affinity, which in turn influences their reactivity and chemical behaviours - key attributes leveraged in a multitude of applications and uses as detailed above.
Uses of Other Non-Metals:
Nitrogen: Used to produce ammonia for refrigeration.
Phosphorus: Used in many drugs and medicines.
Boron: Main ingredient of boric acid, used in antibiotic powder for the treatment of cuts and bruises.
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