Question

IV) Give reasons:
1) Sodium and potassium are stored in kerosene.

2) Silver objects become black and lose their shine with the passage of time.

3) Bells are made up of metals

4) The screwdriver used by electricians has a wooden or plastic handle.

5) Copper is used for making electric wires.

Answer 1

Answer:

1)sodium and potassium are stored in kerosene because these metals are very reactive

2)Silver object becomes black because due the reaction with oxygen.

4) because plastic is the bad conductor electricity.

5) because copper is the good conductor of electricity.

Answer 2

Answer:

1... both are highly reactive metal so to prevent this explosive rexn ,sodium kept immersed in kerosene becz Na does not react with it

2....silver turns black when kept in the air becoz silver react With sulphur compound such as h2s present in air and form silver sulphide

3....bell are made up of.metal becoz metals have high elasticity as well as high inertia so produce sound more tym

4...becoz it is.made of iron which is good conductor of heat and electricity and prevent electric shock

5...becoz it's property make it's an ideal metal, excellent conductor of electricity