Question

Which of the following pairs of ions cannot be separated by $H_2S$ in dilute $HCl$ ?

• A. $Bi^{3+}$, $Sn^{4+}$
• B. $Al^{3+}$, $Hg^{2+}$
• C. $Cu^{2+}$, $Zn^{2+}$
• D. $Ni^{2+}$, $Cu^{2+}$

Answer 1

Answer: (A)

(a) $Bi ^{3+}$ and $Sn ^{4+}$ cannot be separated $by H _{2} S$ in dilute $HCl$, because both are present in second group and both are precipitated by $H _{2} S$ in dil. $HCl$ as $Bi _{2} S _{3}$ and $SnS _{2}$.

(b) $Al ^{3+}$ is not precipitated by $H _{2} S$ in dil $HCl$ whereas $Hg ^{2+}$ is precipitated as $HgS$.

(c) $Zn ^{2+}$ is not precipitated, but $Cu ^{2+}$ is precipitated as CuS.

(d) $Ni ^{2+}$ is not precipitated, but $Cu ^{2+}$ is precipitated as mention earlier.