Lassaigne's test is used in the qualitative analysis to detect

Options

A. HCl
B. `H_(2)S` (alkaline)
C. `(NH_(4))_(2)S`
D. `None of these

Answer

B

Explanation

In presence of `NH_(4) OH`, dissociation of `H_(2)S` is remarkably high so increases the solubility product of `IV^(th)` group sulphides `H_(2)S hArr 2H^(+) + S^(2-)`
`NH_(4) OH to NH_(4)^(+) + OH^(-)`
`OH^(-) + H^(+) to H_(2)O`