Question

What is silver nitrate test?

Answer 1

Silver nitrate test is carried out to detect the type of halide ion in a given solution.

The solution is first acidified by adding dilute $HN{O}_3$ followed by silver nitrate solution. $F^{-},C{l}^{-},B{r}^{-}$ & $I^{-}$ react as given below.

$A{g}_{\left(ag\right)}^{+}+F_{\left(ag\right)}^{-}⟶AgF$ (No precipitate as it is soluble.)

$A{g}_{\left(ag\right)}^{+}+C{l}_{\left(ag\right)}^{-}⟶AgC{l}_{\left(s\right)}$ (white precipitate.)

$A{g}_{\left(ag\right)}^{+}+B{r}_{\left(ag\right)}^{-}⟶AgB{r}_{\left(s\right)}$ (pale cream precipitate.) precipitate.)

$A{g}_{\left(ag\right)}^{+}+I_{\left(ag\right)}^{-}⟶Ag{I}_{\left(s\right)}$ (pale yellow precipitate.)

The precipitate is treated with $N{H}_3$ solution to confirm the halide. The following observation is done.

$AgCl⟶$ dissolves to give a colorless colution.

$AgBr⟶$ dissolves in conc $N{H}_3$ to give a colorless solution.

$AgI⟶$ Insoluble in $N{H}_3$ of any concentration.