# The ion that cannot be precipitated by both $HCl$ and $H_2S$

(a) $Pb^{2+}$
(b) $Cu^+$
(c) $Ag^+$
(d) $Sn^{2+}$

Answer: $Sn^{2+}$

$Pb^{2+}$ and $Ag^+$ can be precipitated both by $HCl$ and $H_2S$. $Cu^{2+}$ dissolves in conc. HCl but is precipitated on dlution. It is also precipitated by $H_2S$. $Sn^{2+}$ is not precipitated by HCl. It is precipitated by $H_2S$ only.