Question

To a solution of substance, gradual addition of ammonium hydroxide results in a black precipitate which does not dissolve in excess of `NH_(4)OH`. However, when HCl is added to the original solution, a white precipitate is formed. The solution contained
A. Lead salt
B. Silver salt
C. Mercurous salt
D. Copper salt

Answer 1

Correct Answer - C
`Hg_(2)Cl_(2)` is white insoluble salt.
`Hg_(2)Cl_(2)+2NH_(4)OH to Hg+HGunderset("Black")ubrace((NH_(2))Cl+NH_(4)Cl)+2H_(2)O`