A Problem on Salt Analysis! 2

Brownish black oxide $(A)$ $+$ dil. $\ce{HCl}$ $\rightarrow$ green coloured solution $(B)$ $+$ gas $(C)$

$(B)$ $+$ aq. $\ce{N{H}_{3} +{H}_{2}S}$ gas $\rightarrow$ black ppt $(D)$

$(B) +$ aq $\ce{N{H}_{3}} \rightarrow$ green ppt $(E)$ soluble in excess of aq $\ce{N{H}_{3}}$

$(C) +$ aq $\ce{KI} \rightarrow$ reddish brown solution $(F)$

Find the molecular weight of compound $(A)$

Two more problems on Salt Analysis are as follows:

1. A Problem on Salt Analysis!

2. A Problem on Salt Analysis! 3