Question

A metal $X$ is known to make an oxide which reacts with both $HCl$ and $NaOH$. The metal reacts with steam to evolve Hydrogen gas. When the metal $X$ is reacted with Zinc Sulphate, it displaces $Zn$. Find $X$ and justify your answer by showing balanced reactions of processes mentioned in the question.

Answer 1

Generally $Al$ and $Zn$ are known to form amphoteric oxides which react with both acids and bases, so $X$ can be either $Al$ or $Zn$. But it has been mentioned in the last part of the question that $X$ displaces $Zn$ from its solution, so it has to be $Al$.

The reactions are as follows-

Aluminium oxide with $HCl$ and $NaOH$,

$A{l}_2{O}_3+6HCl\to 2AlC{l}_3+3H_{2}O$

$A{l}_2{O}_3+2NaOH\to 2NaAl{O}_2+H_{2}O$

Aluminium with steam

$2Al\left(s\right)+3H_{2}O\left(g\right)\to A{l}_2{O}_3\left(s\right)+3H_2\left(g\right)$

Aluminium with Zinc Sulphate

$2Al\left(s\right)+3ZnS{O}_4\left(aq\right)\to A{l}_2\left(S{O}_4{)}_3\right(aq)+3Zn(s)$