A mixture consist of a yellow solid [A] and colourless solid [B] which given lilac colour in flame. The miture given a black precipiate [C] on passing `H_(2)S` gas. The precipitate [C] is soluble in aqura region and on evaporating and on adding `SnCl_(2)`, gives greyish black precipitate [D]. The misture solution on reacing with `NH_(4)OH` gives a brown precipiates. The sodium extract of the mixture with `C Cl_(4)//FeCl_(3)` given violet layer. The extract also given yellow precicitate with `AgNO_(3)` solution which is insoluble in `NH_(3)`.
The black precipitate [c] is of :

Options

A. Mercurous sulphide
B. Mercuric sulphide.
C. Bismuth sulphide
D. Lead sulphide.

Answer

B

Explanation

(b) `Hgl_(2)` reacts with `H_(2)S` to give a black precipitate [C] of merucric sulphide (HgS) `HgI_(2)+H_(2)Srarrunderset([C])underset("Black ppt.")(HgS)+2HI`