When a brown compound of manganese (A) is treated with HCL it gives a gas (B). The gas taken in excess, reacts with NH3 to give an explosive compound (C). Identify compounds A, B and C.

Thinking Process

This problem is based on the properties of MnO2, and preparation of NCL3

NEETprep Answer: MnO2 is the brown compound of Mn which reacts with HCL to give   gas.
This gas forms an explosive compound NCL3  when treated with NH3
Thus, A= MnO2 ; B= CL2 ; C=NCL3 and reactions are as follows
(i) MnO2 + 4HCL  MnCL2 + CL2+H2O

(ii) NH3 +3CL2  NCL3 + 3HCL
                (Excess)  (C)