An aqueous solution of gas (X) shows the following reactions. (i) It turns red litmus blue.
(ii) When added in excess to a copper sulphate solution, a deep blue colour is obtained.
(iii) On addition of `FeCl_(3)` solution, a brown precipitate , soluble in dilute `HNO_(3)` is obtained.
Identify (X) and give equations for the reactions at step (ii) and (iii).

Explanation

i) Aqueous solution of the gas X turns red litmus blue indicating the basic nature of the gas.
ii) The fact that the aqueous solution of X gives deep blue colour with copper sulphate solution indicates the gas X is ammonia `NH_(-3)`.
`CuSO_(4)+4NH_(3(aq))rarrCu(OH)_(3)+3NH_(4)Cl`
iii) The nature of the gas X as ammonia is in accordance with the given fact its aqueous solution gives brown precipitate with ferric chloride. The precipitate is soluble in dilute nitric acid.
`ubrace(3NH_(3)+3H_(2)O)_("aq. solution of X ")+FeCl_(3)rarrFe(OH)_(3)+3NH_(4)Cl`
`Fe(OH)_(3)+3HNO_(3)rarrFe(NO_(3))_(2)+3H_(2)O`