Which of the following pairs will give displacement reactions ?

Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.

$(a)$ What will be the action of gas on

$(i)$ dry litmus paper ?

$(ii)$ moist litmus paper ?

$(b)$ Write a balanced chemical equation for the reaction taking place.

Give an example of a metal which

$(i)$ is a liquid at room temperature.

$(ii)$ can be easily cut with a knife.

$(iii)$ is the best conductor of heat.

$(iv)$ is a poor conduct of heat.

Define the following terms.

$(i)$ Mineral       $(ii)$ Ore         $(iii)$ Gangue

Write equations for the reactions of

$(i)$ iron with steam

$(ii)$ calcium and potassium with water

Food cans are coated with tin and not with zinc because