Question

When excess of SnCl₂ is added to a solution of HgCl₂, a
white precipitate turning to grey is obtained. This grey colour
is due to the formation of
(a) Hg₂Cl₂ (b) SnCl₄
(c) Sn (d) Hg.

Answer 1

This grey colour  is due to the formation of  Hg. So option d is correct.

Explanation:

When excess SnCl₂ is added to HgCl₂ white precipitates are turning to grey and this is due to the formation of mercury (Hg). This mercury is in metallic form.

Chemical equation:

2HgCl₂  +  SnCl₂ →  SnCl₄ + Hg₂Cl₂ (White precipitate)

Chemical equation: (excess SnCl₂)

Hg₂Cl₂  +  SnCl₂ →  SnCl₄ + 2Hg (grey precipitate)