Question

Three separate samples of a solution of a single salt gave these results. One formed a white ppt. with excess ammonia solution, one formed a white ppt. with dil. NaCl solution and one formed a black ppt. with `H_(2)S` . The salt could be
A. `AgNO_(3)`
B. `Pb(NO_(3))_(2)`
C. `Hg(NO_(3))_(2)`
D. `MnSO_(4)`

Answer 1

`Pb(NO_(3))_(2) +2NH_(4)OH to underset("White ppt.")(Pb(OH)_(2) darr)+2NH_(4)NO_(3)`
`Pb(NO_(3))_2 +H_(2)S to underset("White ppt.")(PbS darr)+2NaNO_(3)`
`Pb(NO_(3))_(2) + H_(2)S to underset("Black ppt.")(PbS darr)+2NaNO_(3)`