NCERT Class VIII Science Solutions: Chapter 4-Materials: Metals and Non-Metals Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 5:

Some properties are listed in the following Table. Distinguish between metals and nonmetals on the basis of these properties.

Distinguish between Metals and Nonmetals
PropertiesMetalsNon-metals
Appearance
Hardness
Malleability
Ductility
Heat Conduction
Conduction of Electricity.

Answer:

Distinguish between Metals and Nonmetals Answer
PropertiesMetalsNon-metals
AppearanceLustrousDull
HardnessHardSoft
MalleabilityMalleableNot malleable
DuctilityDuctileNot Ductile
Heat ConductionGood ConductorBad Conductor
Conduction of Electricity.Good ConductorBad Conductor

Question 6:

Give reasons for the following:

  1. Aluminium foils are used to wrap food items.
  2. Immersion rods for heating liquids are made up of metallic substances.
  3. Copper cannot displace zinc from its salt solution.
  4. Sodium and potassium are stored in kerosene.

Answer:

  1. Aluminium foils are used to wrap food items because aluminium is highly malleable. It can be beaten into thin sheets. Moreover, it does not react with food.
Image Result for Aluminium Foils Are Used to Wrap Food Items …
  1. Metals are good conductors of heat and electricity. Therefore, immersion rods for heating liquids are made of metallic substances.
Image Result for Immersion Rods for Heating Liquids Are Made …
  1. The reactivity of zinc is higher than copper. Only a metal of higher reactivity can displace a metal of lower reactivity from its salt solution. So, copper cannot displace zinc from zinc sulphate solution.
Image Result for Copper Cannot Displace Zinc from Its Salt S …
  1. Sodium and potassium are highly reactive metals. They can catch fire even when they come in contact with air. So, they have to be kept in kerosene.
Image Result for Sodium and Potassium Are Stored in Kerosene …

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