• # question_answer Concentrated aqueous sodium hydroxide can separate mixture of [MNR 1995] A) $A{{l}^{3+}}$ and $S{{n}^{2+}}$ B) $A{{l}^{3+}}$ and $F{{e}^{3+}}$ C) $A{{l}^{3+}}$ and $Z{{n}^{2+}}$ D) $Z{{n}^{2+}}$ and $P{{b}^{2+}}$

$NaOH+A{{l}^{+3}}\,\to \,\underset{(\text{Soluble}\,\text{in}\,NaOH)}{\mathop{\underset{\text{Sod}\text{. metaaluminate}}{\mathop{NaAl{{O}_{2}}}}\,}}\,$ $NaOH+F{{e}^{+3}}\,\to$No reaction (Insoluble in NaOH)