Copper sulphate crystals available in the market are blue coloured crystals. By careful heating, they turn to white colour. Which one of the following is responsible for the blue colour ?

An iron nail dipped in copper sulphate solution turns brown. This is due to which one of the following types of reactions?

A liquid is heated up to a certain temperature. Which one of the following situation would correspond to the boiling of the liquid?

Which one of the following materials is present in a guard tube (drying tube) that is used for preparation of HCl gas?

Which one of the following compounds is used in 'black and white' photography?

Which one of the following statements regarding Bleaching powder and D.D.T. is correct ?