Question

Aluminium and potassium hydroxide reacts with water to form the potassium salt $\left(X\right)$. Then with the addition of sulphuric acid in presence of water, it is converted into a precipitate known as alum. Identify $\left(X\right)$.

• A. $KAl(OH{)}_4$
• B. $Al(OH{)}_3$
• C. $K_{2}Al(OH{)}_4$
• D. None of the above

Answer 1

The correct option is A $KAl(OH{)}_4$

Option $\left(A\right)$ is correct.

$X$ is $2KAl(OH{)}_4$.

$2Al\left(s\right)+2KOH\left(aq\right)+6H_{2}O\left(l\right)\to 2KAl\left(OH{)}_4\right[X]+3H_2$

$KAl(OH{)}_4+H_{2}S{O}_4+12H_{2}O\to KAl(S{O}_4{)}_2.12H_{2}O\left[alum\right]$