Identify the substance italicized : The catalyst used to oxidize ammonia.

Fill in the blank with the choices given in the bracket: Ammonia reacts with excess chlorine to form ……………. [nitrogen / nitrogen trichloride / ammonium chloride]

Name the gas evolved when : Ammonia reacts with heated copper [II] oxide.

Give a reason why —

(i) Concentrated sulphuric acid, is not used for drying ammonia gas.

(ii) Ammonia gas is not collected over water.