Metals and Non metals Important 25 Questions with Solution

Here are 25 moderate-level questions with answers on the topic of “Metals and Non-Metals” for Class X students:

Questions and Answers

1. Q: What is the difference between a metal and a non-metal in terms of electrical conductivity?
   A: Metals are generally good conductors of electricity due to the presence of free electrons, while non-metals are poor conductors as they lack free electrons.
2. Q: Give two examples of metals that do not corrode easily.
   A: Gold and platinum do not corrode easily.
3. Q: Why are metals malleable and ductile, whereas non-metals are not?
   A: Metals have layers of atoms that can slide over each other without breaking bonds, making them malleable and ductile. Non-metals lack this arrangement, making them brittle.
4. Q: Name one metal and one non-metal which are liquid at room temperature.
   A: Metal – Mercury (Hg); Non-metal – Bromine (Br).
5. Q: Explain why sodium and potassium are stored in kerosene.
   A: Sodium and potassium are highly reactive and can react vigorously with air and moisture; storing them in kerosene prevents these reactions.
6. Q: Write the chemical equation for the reaction of magnesium with water.
   A: (when reacted with hot water).
7. Q: What is an amphoteric oxide? Give an example.
   A: An amphoteric oxide reacts with both acids and bases to form salt and water. Example: Aluminium oxide ().
8. Q: Why does copper not react with dilute hydrochloric acid?
   A: Copper is less reactive than hydrogen, so it cannot displace hydrogen from dilute hydrochloric acid.
9. Q: Name one metal and one non-metal used in the purification of water.
   A: Metal – Aluminium (used as a coagulant); Non-metal – Chlorine (used for disinfection).
10. Q: Describe the reaction of calcium with water.
    A: Calcium reacts with water to form calcium hydroxide and hydrogen gas.
    .
11. Q: What is the difference between a mineral and an ore?
    A: A mineral is a naturally occurring substance with a definite chemical composition. An ore contains enough metal in it to be profitably extracted.
12. Q: Why is aluminium used for making electrical cables?
    A: Aluminium is used because it is a good conductor of electricity, lightweight, and relatively cheap.
13. Q: What happens when a metal carbonate reacts with an acid?
    A: It forms a salt, water, and carbon dioxide.
    Example:
    .
14. Q: Write two chemical properties of non-metals.
    A: (1) Non-metals form acidic or neutral oxides.
    (2) They gain electrons to form negative ions (anions).
15. Q: Explain why metals are used for making cooking utensils.
    A: Metals are good conductors of heat and have high melting points, making them suitable for cooking.
16. Q: How does zinc react with dilute sulphuric acid?
    A: Zinc reacts with dilute sulphuric acid to produce zinc sulphate and hydrogen gas.
    .
17. Q: What is alloying? Why is it done?
    A: Alloying is the process of mixing a metal with other metals or non-metals to enhance its properties, such as strength, corrosion resistance, and hardness.
18. Q: Why are non-metals not used for making wires?
    A: Non-metals are poor conductors of electricity and are brittle, making them unsuitable for wiring.
19. Q: What happens when iron nails are placed in copper sulphate solution?
    A: Iron displaces copper from copper sulphate solution, forming iron sulphate and copper deposits.
    .
20. Q: Give one use each of chlorine and sulphur.
    A: Chlorine – Used for water purification; Sulphur – Used in the manufacture of sulphuric acid.
21. Q: Define corrosion. Give one method to prevent it.
    A: Corrosion is the gradual degradation of metals due to chemical reactions with their environment. It can be prevented by painting or coating the metal.
22. Q: What happens when aluminium reacts with dilute hydrochloric acid?
    A: It forms aluminium chloride and hydrogen gas.
    .
23. Q: Why is hydrogen gas not evolved when a metal reacts with nitric acid?
    A: Nitric acid is a strong oxidizing agent and it oxidizes hydrogen to water instead of letting it evolve as gas.
24. Q: Explain the term ‘electrolytic refining’ with an example.
    A: Electrolytic refining is the process of purifying a metal using electrolysis. Example: Copper is refined by making it the anode and a pure copper strip as the cathode in an electrolyte of copper sulphate.
25. Q: What are metalloids? Give two examples.
    A: Metalloids have properties of both metals and non-metals. Examples: Silicon (Si), Germanium (Ge).
26. Here are 15 difficult-level questions and answers on the topic of “Metals and Non-Metals” for Class X students:
    
    Questions and Answers
    
    1. Q: Describe the thermite reaction and mention its applications.
    A: The thermite reaction is a highly exothermic reaction in which aluminium powder reacts with iron(III) oxide to produce molten iron and aluminium oxide.
    Reaction:
    
    It is used in welding railway tracks and in repairing cracked machinery parts.
    
    
    2. Q: Explain why an aqueous solution of sodium chloride conducts electricity, but solid sodium chloride does not.
    A: In solid sodium chloride, ions are held tightly in a lattice structure, so they cannot move freely. However, in an aqueous solution, the ions are free to move, allowing for electrical conductivity.
    
    
    3. Q: Why is aluminium oxide considered an amphoteric oxide? Illustrate with balanced chemical equations.
    A: Aluminium oxide reacts with both acids and bases, exhibiting amphoteric behavior.
    Reaction with acid (HCl):
    
    Reaction with base (NaOH):
    .
    
    
    4. Q: Explain the mechanism of corrosion of iron in the presence of water and oxygen.
    A: Corrosion of iron occurs through the following process:
    
    Iron reacts with oxygen and water to form hydrated iron(III) oxide (rust).
    
    Anodic Reaction:
    
    Cathodic Reaction: .
    The Fe^{2+} ions are oxidized further in the presence of water and oxygen to form rust.
    
    
    
    5. Q: Give reasons why metals form basic oxides while non-metals form acidic oxides.
    A: Metals lose electrons to form positive ions and form basic oxides which react with acids to form salts and water. Non-metals gain electrons to form negative ions and form acidic oxides which react with bases to form salts and water.
    
    
    6. Q: Differentiate between roasting and calcination processes used in metallurgy.
    A: Roasting is the process of heating an ore in the presence of oxygen, typically for sulphide ores (e.g., ). Calcination is heating an ore in the absence of oxygen, typically for carbonate ores (e.g., ).
    
    
    7. Q: What is the role of flux in the extraction of metals? Give an example.
    A: Flux is used in metallurgy to remove impurities by forming a slag. Example: In iron extraction, limestone acts as a flux to remove silica impurities by forming calcium silicate (slag).
    
    
    8. Q: Why is zinc more reactive than iron, but iron is preferred for galvanization?
    A: Zinc is more reactive and forms a protective layer of zinc oxide that prevents further corrosion. Iron is preferred for galvanization because the layer of zinc provides a sacrificial coating, corroding before the iron.
    
    
    9. Q: How does the reactivity series help in predicting the outcomes of displacement reactions?
    A: The reactivity series ranks metals based on their reactivity. A more reactive metal displaces a less reactive metal from its compound. For example, zinc displaces copper from copper sulphate solution, but copper cannot displace zinc from zinc sulphate solution.
    
    
    10. Q: Explain why alloys are harder than pure metals.
    A: In alloys, atoms of different sizes are mixed, which distorts the regular arrangement of the atoms in pure metals, making it more difficult for the layers to slide over each other, increasing hardness.
    
    
    11. Q: Describe the reaction of chlorine with cold and hot concentrated sodium hydroxide.
    A:
    
    Cold solution:
    .
    
    Hot solution:
    .
    
    
    
    12. Q: Why is tungsten used for making the filament of electric bulbs?
    A: Tungsten has a high melting point (~3422°C) and good electrical conductivity, making it suitable for withstanding high temperatures in electric bulbs without melting.
    
    
    13. Q: Explain why noble gases are not considered metals or non-metals.
    A: Noble gases are inert and do not exhibit typical metallic or non-metallic properties due to their complete valence electron shells, making them chemically unreactive.
    
    
    14. Q: What is galvanic corrosion, and how can it be prevented?
    A: Galvanic corrosion occurs when two different metals are electrically connected in an electrolyte, causing the more reactive metal to corrode. It can be prevented by using insulating materials, coatings, or sacrificial anodes.
    
    
    15. Q: Describe the process of electroplating and mention its uses.
    A: Electroplating involves depositing a layer of metal onto another material using an electric current. For example, coating iron with chromium for a decorative finish and corrosion resistance. It is widely used in jewelry, automotive parts, and household utensils.