1. Which of the following metals is the most reactive?
(A) Copper
(B) Silver
(C) Potassium
(D) Gold
Answer: (C) Potassium
Explanation: Potassium is near the top of the reactivity series and reacts very vigorously.
2. Which of the following metals is the least reactive?
(A) Sodium
(B) Zinc
(C) Gold
(D) Magnesium
Answer: (C) Gold
Explanation: Gold is a very unreactive metal and is therefore found in native form.
3. Which metal reacts vigorously with cold water?
(A) Copper
(B) Potassium
(C) Silver
(D) Gold
Answer: (B) Potassium
Explanation: Potassium reacts very rapidly with cold water, producing potassium hydroxide and hydrogen.
4. Which metal is commonly stored under kerosene oil?
(A) Copper
(B) Sodium
(C) Iron
(D) Zinc
Answer: (B) Sodium
Explanation: Sodium reacts vigorously with oxygen and moisture, so it is stored under kerosene.
5. Which metal reacts with dilute hydrochloric acid to produce hydrogen gas?
(A) Copper
(B) Silver
(C) Zinc
(D) Gold
Answer: (C) Zinc
Explanation: Zinc is above hydrogen in the reactivity series and can displace hydrogen from dilute acids.
6. Which of the following metals does not normally liberate hydrogen from dilute hydrochloric acid?
(A) Magnesium
(B) Zinc
(C) Iron
(D) Copper
Answer: (D) Copper
Explanation: Copper is below hydrogen in the reactivity series and does not displace hydrogen from dilute HCl.
7. When an iron nail is placed in copper sulphate solution, the solution gradually changes because:
(A) Copper displaces iron
(B) Iron displaces copper
(C) Both metals evaporate
(D) No reaction occurs
Answer: (B) Iron displaces copper
Explanation: Iron is more reactive than copper and displaces copper from copper sulphate.
8. The reddish-brown coating formed on iron due to corrosion is called:
(A) Patina
(B) Rust
(C) Zinc oxide
(D) Iron sulphide
Answer: (B) Rust
Explanation: Rust is mainly hydrated iron(III) oxide formed in the presence of oxygen and moisture.
9. Rusting of iron requires:
(A) Oxygen and moisture
(B) Nitrogen and sunlight
(C) Hydrogen and carbon dioxide
(D) Only oxygen
Answer: (A) Oxygen and moisture
10. Which method protects iron from rusting by coating it with zinc?
(A) Alloying
(B) Galvanization
(C) Electrolysis
(D) Distillation
Answer: (B) Galvanization
Explanation: Galvanization coats iron or steel with zinc, protecting it from corrosion.
11. Which of the following is commonly used to prevent rusting of iron by forming a protective coating?
(A) Painting
(B) Boiling
(C) Crushing
(D) Melting
Answer: (A) Painting
12. Stainless steel is an alloy mainly containing:
(A) Iron, chromium and usually nickel
(B) Copper and zinc only
(C) Aluminium and copper only
(D) Iron and sodium
Answer: (A) Iron, chromium and usually nickel
Explanation: Chromium provides corrosion resistance; many stainless steels also contain nickel.
13. Brass is an alloy of:
(A) Copper and zinc
(B) Copper and tin
(C) Iron and carbon
(D) Aluminium and magnesium
Answer: (A) Copper and zinc
14. Bronze is mainly an alloy of:
(A) Copper and zinc
(B) Copper and tin
(C) Iron and chromium
(D) Aluminium and copper
Answer: (B) Copper and tin
15. Which alloy is commonly used for making electrical wires and components because of its good electrical conductivity?
(A) Copper-based alloys only
(B) Pure copper
(C) Cast iron
(D) Brass only
Answer: (B) Pure copper
Explanation: Copper has very high electrical conductivity and is widely used in electrical wiring.
16. Aluminium is widely used for making aircraft bodies mainly because it is:
(A) Very heavy and highly reactive
(B) Light and corrosion-resistant
(C) A poor conductor of electricity
(D) Easily dissolved in water
Answer: (B) Light and corrosion-resistant
17. Which metal is commonly used for electrical wiring because of its excellent electrical conductivity?
(A) Copper
(B) Iron
(C) Lead
(D) Mercury
Answer: (A) Copper
18. The extraction of highly reactive metals such as sodium and aluminium is generally carried out by:
(A) Heating their ores with carbon
(B) Electrolysis
(C) Filtration
(D) Simple distillation
Answer: (B) Electrolysis
Explanation: Highly reactive metals cannot generally be extracted by reducing their compounds with carbon; electrolysis is used.
19. Which metal is extracted from its ore mainly by electrolytic reduction?
(A) Sodium
(B) Copper
(C) Iron
(D) Zinc
Answer: (A) Sodium
20. Which of the following correctly matches the metal with its common use?
(A) Copper — Electrical wiring
(B) Aluminium — Aircraft bodies
(C) Zinc — Galvanization
(D) All of the above
Answer: (D) All of the above
21. Why is aluminium widely used for making cooking utensils?
(A) It has a relatively high thermal conductivity and is lightweight
(B) It reacts violently with water
(C) It has no thermal conductivity
(D) It is a non-metal
Answer: (A) It has a relatively high thermal conductivity and is lightweight
22. Which metal is used in the manufacture of electrical cables because of its good conductivity and ductility?
(A) Copper
(B) Sodium
(C) Calcium
(D) Potassium
Answer: (A) Copper
23. Which metal is commonly used to coat iron sheets to prevent corrosion?
(A) Zinc
(B) Sodium
(C) Potassium
(D) Mercury
Answer: (A) Zinc
24. Why does stainless steel resist corrosion better than ordinary iron?
(A) It contains chromium that forms a protective oxide layer
(B) It contains sodium
(C) It reacts rapidly with water
(D) It contains no metal
Answer: (A) It contains chromium that forms a protective oxide layer
25. Which of the following is not an alloy?
(A) Brass
(B) Bronze
(C) Stainless steel
(D) Copper
Answer: (D) Copper
Explanation: Copper is an element, whereas brass, bronze and stainless steel are alloys.
Quick Revision — Metals & Non-metals
| Fact | Remember |
|---|---|
| Most reactive common metals | K, Na, Ca |
| Highly unreactive metal | Gold |
| Sodium storage | Under kerosene |
| Iron + CuSO₄ | Iron displaces copper |
| Rusting | Iron + oxygen + moisture |
| Galvanization | Zinc coating on iron |
| Brass | Copper + Zinc |
| Bronze | Copper + Tin |
| Stainless steel | Iron + Chromium + usually Nickel |
| Copper | Electrical wiring |
| Aluminium | Aircraft, utensils |
| Zinc | Galvanization |
| Gold | Jewellery, corrosion-resistant |
| Sodium | Highly reactive; stored under kerosene |
| Highly reactive metal extraction | Electrolysis |
| Copper extraction | Mainly from sulphide ores; roasting/smelting and refining |
| Rust prevention | Painting, oiling, galvanization, alloying |
| Chromium in stainless steel | Corrosion resistance |