A white curdy precipitate with $\mathrm{AgNO}{}_3$ that readily dissolves in dilute aqueous ammonia indicates the presence of

$\mathrm{AgCl}$ is white and dissolves in dilute $\mathrm{NH}{}_3$ as $[\mathrm{Ag}(\mathrm{NH}{}_3){}_2]{}^{+}$. $\mathrm{AgBr}$ is pale yellow and only sparingly soluble, $\mathrm{AgI}$ is yellow and insoluble, and sulphate gives no precipitate with silver nitrate in dilute solution.