Phenol is heated with concentrated sulphuric acid at `110^(@)C`. The major product formed is

Fill in the blanks with the choices given in bracket : when sodium chloride is heated with concentrated sulphuric acid below 200^(@)C , one of the products formed is _____ [ sodium hydrogen sulphate /sodium sulphate /chlorine]

When 2-butanol is heated with an excess of concentrated sulphuric acid, the main product is

Chloro benzene is sulphonated with fuming sulphuric acid. The major product formed is

When potassium ferrocyanide crystals are heated with concentrated sulphuric acid, the gas evolved is

When sodium chloride is heated with concentrated sulphuric acid, the gas liberated is

Copper turnings when heated with concentrated sulphuric acid will give