The World of Metals and Non-metals

Metals & Non-Metals – Question Bank

1. Multiple Choice

Which metal is commonly used for packing food because thin sheets fold easily and cost less?

1. Aluminium
2. Copper
3. Iron
4. Gold

Answer: Aluminium is light, cheap, non-toxic and very malleable, so it is ideal for safe food packaging.

2. Multiple Choice

Which metal catches fire on contact with water?

1. Copper
2. Aluminium
3. Zinc
4. Sodium

Answer: Sodium reacts violently with water, generating heat and hydrogen gas that ignites instantly, causing the metal to burn.

3. True / False with Reason

1. Aluminium and copper are non-metals used for utensils.  
2. Metal oxides dissolved in water turn blue litmus paper red.  
3. Oxygen is a non-metal essential for breathing.  
4. Copper vessels conduct heat quickly while boiling water.  

Answer:
(a) F – they are metals, valued for strength and conductivity.
(b) F – most metal-oxide solutions are basic, turning red litmus blue.
(c) T – oxygen supports respiration in all living beings.
(d) T – copper’s high thermal conductivity heats water rapidly.

4. Short Answer

Why are only a few metals suitable for jewellery?

Answer: Gold, silver and platinum resist corrosion, stay shiny, are highly malleable and rarely cause skin allergy, making them perfect for ornaments.

5. Match the Columns

Column I – Use	Column II – Jumbled Name
(a) Electrical wiring	E N X Y G O
(b) Most malleable, ductile	O G D L
(c) Needed for life processes	N E C O H I R L
(d) Fertiliser nutrient	P E P O C R
(e) Water purification	T E N G O I R

Answer Table:

Use	Correct Element
(a) Electrical wiring	Copper
(b) Most malleable / ductile	Gold
(c) Needed for life processes	Oxygen
(d) Fertiliser nutrient	Nitrogen
(e) Water purification	Chlorine

6. Reaction with Oxygen – Compare

Reactant	Word Equation	Chemical Equation	Nature of Product
Magnesium	Magnesium + Oxygen → Magnesium oxide	2 Mg + O2 → 2 MgO	Basic; solution turns red litmus blue
Sulphur	Sulphur + Oxygen → Sulphur dioxide	S + O2 → SO2	Acidic; solution turns blue litmus red

Key Difference: Magnesium gives white basic oxide, but sulphur produces acidic, pungent sulphur dioxide gas.

7. Burning Magnesium – Observation Flow

Step	Observation
Burn magnesium ribbon in air	Blinding white flame; white ash forms
Add ash to water	Slightly alkaline suspension forms
Test with blue litmus	No colour change
Test with red litmus	Turns blue, confirming basicity

8. Application Question

Choose the best material for a pan to boil water and justify.

Answer: Copper conducts heat fastest, withstands direct flame, resists rust better than iron and has a safe melting point, so it is ideal for pans.

9. Rusting Experiment

Three identical iron nails are dipped separately in oil, water and vinegar. Which nail will not rust? Why?

Answer: The nail in oil will not rust because oil blocks oxygen and moisture, both necessary for iron to oxidise.

10. Metals vs Non-Metals – Uses

Answer: Metals are strong, shiny, conduct heat and electricity, so they make wires, utensils and machines. Reactive non-metals like oxygen, nitrogen and chlorine aid breathing, fertilising and water disinfection.

11. Can Sulphur Protect Iron?

Can sulphur coat iron to prevent rusting like zinc galvanisation? Explain.

Answer: No. Sulphur layer is brittle and porous, allowing moisture through; it even weakens iron, unlike zinc’s tight, protective coating.

12. Heating Iron before Forging

Why does an ironsmith heat iron before shaping tools?

Answer: Heating softens iron, lowering its yield strength so the smith can hammer it into sharp shapes without cracking; the metal hardens again on cooling.