Give reasons : Sodium, potassium and lithium are stored under oil.

Give reasons : Carbonate and sulphide ores are usually converted into oxides during the process of extraction.

What are alloys ?

What chemical process is used for obtaining a metal from its oxide ?

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?