Question

Which of the following ions can be separated by using $N{H}_{4}Cl$ and $N{H}_{4}OH$?

• A. $F{e}^{3+}$ and $C{r}^{3+}$
• B. $C{r}^{3+}$ and $C{o}^{2+}$
• C. $C{r}^{3+}$ and $A{l}^{3+}$
• D. $A{l}^{3+}$ and $B{a}^{2+}$

Answer 1

Answer: (B), (D)

The correct options are
B $C{r}^{3+}$ and $C{o}^{2+}$
D $A{l}^{3+}$ and $B{a}^{2+}$

For third group, the group reagent is $N{H}_{4}Cl+N{H}_{4}OH$
The cations in third group are $F{e}^{3+},A{l}^{3+}$ and $C{r}^{3+}$. These cations can be separated from cations of other groups by using the reagent $N{H}_{4}Cl+N{H}_{4}OH$.

Hence, the correct answer is
(B) $C{r}^{3+}$ and $C{o}^{2+}$
(D) $A{l}^{3+}$ and $B{a}^{2+}$

Options (A) and (C) cannot be separated as the given ions belong to the same group.