Question

(e) ammonia and hydrogen chloride gases are mixed.
A metal nitrate 'A' on heating gives a yellow residue 'B' along with the evolution of a reddish
brown gas 'C' and a colouless gas 'D'. Aqueous solution of 'A' on reaction with potassium
iodide solution forms yellow precipitate of compound 'E'. Identify A,B,C,D and E. (5)​

Answer 1

The metal nitrate is Lead nitrate - Pb(NO3)2.

Lead nitrate on heating gives a yellow residue of PbO (also called litharge) along with brown fumes of NO2. O2 is also formed as one of the products.

The balanced chemical equation is:

2Pb(NO3)2 ---> 2PbO + 4NO2 + 2O2

Here, A is Pb(NO3)2

B is PbO

C is NO2

D is O2

Now Lead nitrate on reaction with Potassium iodide gives a yellow precipitate of Lead iodide.

Pb(NO3)2 + 2KI ---> PbI2 + 2KNO3

So, E is PbI2.