Questions of Multi-Topic Properties and Uses - Questions at the end of the chapter - Chapter 4 Class 7 - The World of Metals and Non-metals (Curiosity)

Last updated at April 25, 2026 by

Q3 (Medium): State with reason(s) whether the following statements are True or False: (i) Aluminium and copper are examples of non-metals used for making utensils and statues. (ii) Metals form oxides when combined with oxygen, the solution of which turns blue litmus paper to red. (iii) Oxygen is a non-metal essential for respiration. (iv) Copper vessels are used for boiling water because they are good conductors of electricity.

Answer:
We have studied that metals and non-metals have different properties and uses . This is why we can identify true and false statements.

💡 Statement Analysis:

(i) False - Aluminium and copper are metals , not non-metals
(ii) False - Metal oxides are basic and turn red litmus blue
(iii) True - Oxygen is a non-metal needed for breathing
(iv) False - Copper vessels are used because they conduct heat well

Metals vs Non-metals Properties Property Metals Non-metals Examples Aluminium, Copper Oxygen, Sulphur Oxide nature Basic oxides Acidic oxides Heat conduction Good conductors Poor conductors Uses Utensils, statues Respiration, burning

Q5 (Easy): Match the uses of metals and non-metals given in Column I with the jumbled names of metals and non-metals given in Column II.

Answer:
We have studied that different materials have specific uses based on their properties . This is why we can match uses with materials.

💡 Matching Table:
Column I (Uses) Column II (Materials) Correct Match
Making wires Copper, Coal, Wood → Copper
Fuel for cooking Iron, Coal, Gold → Coal
Making jewellery Gold, Sulphur, Wood → Gold
Making tools Iron, Oxygen, Coal → Iron
Uses of Materials Metals Uses Non-metals Uses Copper - wires Coal - fuel Gold - jewellery Oxygen - breathing Iron - tools Wood - furniture

Q6 (Medium): What happens when oxygen reacts with magnesium and sulphur. What are the main differences in the nature of products formed?

Answer:
We have studied that metals and non-metals form different types of oxides when they react with oxygen . This is why the products have different natures.

  • Magnesium + Oxygen → Magnesium oxide ( basic )
  • Sulphur + Oxygen → Sulphur dioxide ( acidic )
  • Metal oxides are basic in nature
  • Non-metal oxides are acidic in nature
Oxide Formation Reactions Metal Reaction Magnesium + Oxygen Magnesium Oxide (Basic) Non-metal Reaction Sulphur + Oxygen → Sulphur Dioxide (Acidic)

Q7 (Medium): Complete the following flow chart (related to burning and testing with litmus).

Answer:
We have studied that burning materials in oxygen produces oxides which can be tested with litmus . Based on the science:

Burning and Litmus Testing Step 1 - Burn Material Metal or non-metal burns in oxygen Step 2 - Oxide Forms Metal oxide (basic) or non-metal oxide (acidic) Step 3 - Dissolve in Water Oxide dissolves to form solution Step 4 - Test with Litmus Basic turns red litmus blue, acidic turns blue litmus red Nature of material identified!

Q8 (Medium): You are provided with the following materials. Discuss which material would be your choice to make a pan that is most suitable for boiling water and why? Iron copper sulphur coal plastic wood cardboard

Answer:
We have studied that good conductors of heat are suitable for cooking utensils . This is why copper is the best choice.

💡 Given: Iron | Copper | Sulphur | Coal | Plastic | Wood | Cardboard
  • Copper is the best heat conductor
  • Iron is also good but rusts easily
  • Non-metals like sulphur , coal are poor conductors
  • Plastic , wood , cardboard melt or burn
Pan Material Selection Best Choice Copper - excellent heat conductor Good Choice Iron - good conductor, rusts Poor Choices Non-metals - poor conductors Unsuitable Plastic/Wood - melt/burn

Q10 (Difficult): How do the different properties of metals and non-metals determine their uses in everyday life?

Answer:
We have studied that metals and non-metals have contrasting properties like malleability , conductivity , and sonority . This is why their uses are different.

  • Malleability makes metals suitable for utensils and sheets
  • Good heat conduction makes metals ideal for cooking pans
  • Good electrical conduction makes metals perfect for wires
  • Sonority makes metals useful for bells and musical instruments
  • Non-metals are poor conductors so used for insulation
  • Non-metals like coal burn easily so used as fuel

Conclusion: Properties directly determine the practical applications of materials .

Properties Determine Uses Property → Use Metal Properties → Uses Non-metal Properties → Uses Malleability → Utensils, sheets → Cannot be flattened Heat conduction → Cooking pans → Insulation materials Electrical conduction → Electric wires → Insulator covers Sonority → Bells, instruments → Sound dampening Combustion → Not suitable fuel → Coal for fuel

Q11 (Difficult): One of the methods of protecting iron from getting rusted is to put a thin coating of zinc metal over it. Since sulphur does not react with water, can it be used for this purpose? Justify your answer.

Answer:
We have studied that rusting prevention requires blocking both air and water from reaching iron . This is why sulphur cannot replace zinc coating.

  • Zinc coating reacts with air to form protective layer
  • Sulphur is a non-metal and cannot form metallic coating
  • Sulphur is brittle and will break when iron bends
  • Zinc is malleable and stays attached to iron surface
  • Sulphur does not bond strongly with iron metal

Conclusion: Sulphur cannot replace zinc because it lacks metallic properties needed for protective coating .

Zinc vs Sulphur for Iron Protection Property Zinc Coating Sulphur Coating Material type Metal - malleable Non-metal - brittle Bonding with iron Strong metallic bond Weak attachment Flexibility Bends with iron Breaks when bent Protective layer Forms stable coating Cannot form coating Effectiveness Prevents rusting Cannot prevent rusting

Q12 (Medium): An ironsmith heats a piece of iron and beats it to make a farming tool. Name the property of iron that allows the ironsmith to do so.

Answer:
We have studied that malleability is the property by which materials can be beaten into thin sheets . This is why the ironsmith can heat and beat iron to shape it into farming tools.

  • Iron shows malleability when heated and beaten
  • Metal becomes flat instead of breaking into pieces
  • Farming tools like spades and axes are made this way
  • Heat makes iron more malleable for easy shaping
Making Farming Tools Step 1 - Heat iron Iron heated in coal furnace Step 2 - Beat with hammer Hot iron beaten on hard surface Step 3 - Shape forms Iron flattens and takes tool shape Farming tool ready!
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