On heating compound (A) gives a gas (B) which is a constituent of air.
This gas when treted with 3 moles of hydrogen `(H_(2))` in the presence of a catalyat gives another gas (C ) which is basic in nature. Gas C on further oxidation in moist condition gives a compound (D) which is a part of acid rain. Identify compounds (A) to (D) and also give necessary equations of all the steps involved .

Explanation

(i) Since gas `B` on heating with 3 moles of hydrogen in presence of a catalyst, gives a gas `C` which is basic in nature, therefore, 'C' must be ammonia `(NH_(3))` and gas (B) must be `N_(2)`
`underset((B))(N_(2)) + 3H_(2) overset(Delta, "Catalyst")(to) underset("Ammonia(C)")(2NH_(3))`
(ii) Since gas 'B' (i.e., `N_(2)`) is obtained by heating compound (A) , therefore , compound (A) must be either ammonium nitrite or ammonium dichromate
`underset((A))(NH_(4)) NO_(2) overset(Delta)(to) underset((B))(N_(2)) + 2H_(2)O or (NH_(4))_(2) underset((A))(Cr_(2)) O_(7) overset(Delta)(to) underset((B))(N_(2)) + Cr_(2) O_(3) + 4H_(2)O`
(iii) Since gas 'C', (i.e., `NH_(3)`) on further oxidation in moist conditions gives compound (D) which is a part of acid rain, therefore, compound (D) must be nitric acid `(HNO_(3)`).
`underset((C))4NH_(3)+5O_(2)overset("Oxidation")to4NO+6H_(2)O`
`2NO+O_(2)to2NO_(2),3NO_(3)+H_(2)Otounderset((D))2HNO_(3)+NO`
Thus, `A=NH_(4)NO_(2)or(NH_(4))_(2)Cr_(2)O_(7),B=N_(2),C=NH_(3)andD=HNO_(3)`.