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+4HCLMnCL2+CL2+H2O
Br

(ii)NH3+3CL2NCL3+3HCL
(Excess)(C)