Differentiate between metal and non-metal on the basis of their chemical properties.

Food cans are coated with tin and not with zinc because

A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

Why is sodium kept immersed in kerosene oil ?

Define the following terms.

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