Question

When metal $X$ is treated with sodium hydroxide, a white precipitate $\left(A\right)$ is obtained, which is soluble in excess of $NaOH$ to give soluble complex $\left(B\right)$.

Compound $\left(A\right)$ is soluble in dilute $HCl$ to form compound $\left(C\right)$. The compound $\left(A\right)$ when heated strongly gives $\left(D\right)$, which is used to extract metal.

Identify $\left(X\right),\left(A\right),\left(B\right),\left(C\right)$ and $\left(D\right)$. Write suitable equations to support their identities:

Answer 1

The compounds X, A, B, C and D are aluminium, aluminium hydroxide, sodium tetrahydrozoaluminate (III), aluminium chloride and alumina.

Aluminium reacts with NaOH to form white ppt of $Al(OH{)}_3$.

$Al(OH{)}_3$ reacts with NaOH to form $N{a}^{+}\left[Al\right(OH{)}_4{]}^{-}$.

$Al(OH{)}_3$ reacts with HCL to form $AlC{l}_3$.

When $A{l}_2{O}_3$ is heated, $A{l}_2{O}_3$ is obtained.