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What are alloys?
An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. It is prepared by melting the primary metal and then dissolving the other elements in it in definite proportions. The mixture is then cooled to room temperature. Alloys are used to improve the properties of metals,Read more
An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. It is prepared by melting the primary metal and then dissolving the other elements in it in definite proportions. The mixture is then cooled to room temperature. Alloys are used to improve the properties of metals, such as hardness, strength, and resistance to corrosion. For example, stainless steel is an alloy of iron, nickel, and chromium, which is hard and does not rust. Alloys are also used in making jewelry, where pure gold is alloyed with silver or copper to make it harder.
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See lessWhich of the following pairs will give displacement reactions? (a) NaCl solution and copper metal (b) MgCl2 solution and aluminium metal (c) FeSO4 solution and silver metal (d) AgNO3 solution and copper metal
To determine which pairs will give displacement reactions, we need to consider the reactivity series of metals. According to the given document, if metal A displaces metal B from its solution, it is more reactive than B. (a) NaCl solution and copper metal: Copper is less reactive than sodium, so noRead more
To determine which pairs will give displacement reactions, we need to consider the reactivity series of metals. According to the given document, if metal A displaces metal B from its solution, it is more reactive than B.
(a) NaCl solution and copper metal: Copper is less reactive than sodium, so no displacement reaction will occur.
(b) MgCl2 solution and aluminium metal: Aluminium is more reactive than magnesium, so a displacement reaction will occur.
(c) FeSO4 solution and silver metal: Silver is less reactive than iron, so no displacement reaction will occur.
(d) AgNO3 solution and copper metal: Copper is less reactive than silver, so no displacement reaction will occur.
Therefore, the correct answer is (b) MgCl2 solution and aluminium metal.
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Which of the following methods is suitable for preventing an iron frying pan from rusting? Applying grease Applying paint Applying a coating of zinc All of the above
While the application of grease and paint can prevent iron from rusting, these techniques are not suitable for a frying pan. Therefore, applying a layer of zinc is the most effective way to prevent an iron pan from rusting.
While the application of grease and paint can prevent iron from rusting, these techniques are not suitable for a frying pan. Therefore, applying a layer of zinc is the most effective way to prevent an iron pan from rusting.
See lessAn 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 element that reacts with oxygen to give a compound with a high melting point and is also soluble in water is likely to be silicon. Silicon forms silicon dioxide (SiO2) when it reacts with oxygen, which has a high melting point and is soluble in water. p. 13 p. 4 p. 7
The element that reacts with oxygen to give a compound with a high melting point and is also soluble in water is likely to be silicon. Silicon forms silicon dioxide (SiO2) when it reacts with oxygen, which has a high melting point and is soluble in water.
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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. Zinc has a higher tendency to react with substances, including food acids, which can lead to corrosion and spoilage of the food. Tin, on the other hand, is less reactive and provides a protective barrier againstRead more
Food cans are coated with tin and not with zinc because:
Zinc is more reactive than tin. Zinc has a higher tendency to react with substances, including food acids, which can lead to corrosion and spoilage of the food. Tin, on the other hand, is less reactive and provides a protective barrier against corrosion, ensuring the food remains safe and uncontaminated.
Zinc has a higher melting point than tin. The coating material used for food cans needs to have a lower melting point than the metal of the can itself. This is because the coating needs to be applied and bonded to the can at a lower temperature without affecting the integrity of the can. Tin has a lower melting point compared to zinc, making it more suitable for this purpose.
Therefore, the correct answer is (c) Zinc is more reactive than tin.
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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, you can perform the following tests: Conductivity Test: Connect the battery, bulb, wires, and switch in a circuit. Then, connect the sample to be tested in the circuit. If the bulb lights up, it indicates that theRead more
(a) To distinguish between samples of metals and non-metals using the given materials, you can perform the following tests:
Conductivity Test: Connect the battery, bulb, wires, and switch in a circuit. Then, connect the sample to be tested in the circuit. If the bulb lights up, it indicates that the sample is a metal as metals are good conductors of electricity. If the bulb does not light up, it suggests that the sample is a non-metal.
Hardness Test: Use the hammer to strike the sample. If the sample produces a sound, it is likely to be a metal as metals are sonorous. If the sample does not produce a sound, it is likely to be a non-metal.
(b) These tests can be useful in distinguishing between metals and non-metals to some extent. The conductivity test helps identify metals, which are good conductors of electricity, while the hardness test helps identify metals, which are sonorous. However, these tests may not be conclusive as there can be exceptions and variations in the properties of different metals and non-metals. Therefore, additional tests and observations may be required for a more accurate distinction.
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What are amphoteric oxides? Give two examples of amphoteric oxides.
Amphoteric Oxides Amphoteric oxides are metal oxides that can react with both acids and bases to produce salts and water. They exhibit both acidic and basic properties. Examples of Amphoteric Oxides Aluminium Oxide (Al2O3): It reacts with both acids and bases. For example, it reacts with hydrochloriRead more
Amphoteric Oxides
Amphoteric oxides are metal oxides that can react with both acids and bases to produce salts and water. They exhibit both acidic and basic properties.
Examples of Amphoteric Oxides
Aluminium Oxide (Al2O3): It reacts with both acids and bases. For example, it reacts with hydrochloric acid to form aluminium chloride and water, and it reacts with sodium hydroxide to form sodium aluminate and water.
Zinc Oxide (ZnO): It also exhibits amphoteric properties. It reacts with both acids and bases. For example, it reacts with hydrochloric acid to form zinc chloride and water, and it reacts with sodium hydroxide to form sodium zincate and water.
These are two examples of amphoteric oxides that can react with both acids and bases.
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Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Metals that will displace hydrogen from dilute acids are magnesium and zinc. These metals are more reactive than hydrogen and can replace it in a chemical reaction. On the other hand, metals like copper and silver will not displace hydrogen from dilute acids as they are less reactive than hydrogen.Read more
Metals that will displace hydrogen from dilute acids are magnesium and zinc. These metals are more reactive than hydrogen and can replace it in a chemical reaction. On the other hand, metals like copper and silver will not displace hydrogen from dilute acids as they are less reactive than hydrogen.
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See lessIn the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?
In the electrolytic refining of metal M, the anode would be the impure metal M, while the cathode would be a thin strip of pure metal M. The electrolyte used would be a solution of a metal salt of metal M. p. 16 p. 21
In the electrolytic refining of metal M, the anode would be the impure metal M, while the cathode would be a thin strip of pure metal M. The electrolyte used would be a solution of a metal salt of metal M.
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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.
Action of gas on dry litmus paper: The gas evolved from heating sulphur powder will have no effect on dry litmus paper. It will not change the color of the litmus paper. Action of gas on moist litmus paper: The gas evolved from heating sulphur powder will turn moist litmus paper red. This indicatesRead more
Action of gas on dry litmus paper: The gas evolved from heating sulphur powder will have no effect on dry litmus paper. It will not change the color of the litmus paper.
Action of gas on moist litmus paper: The gas evolved from heating sulphur powder will turn moist litmus paper red. This indicates that the gas is acidic in nature.
Balanced chemical equation for the reaction: The balanced chemical equation for the reaction of sulphur powder with heat can be written as: S(s) + O2(g) → SO2(g)
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