Question

An inorganic Lewis acid (X) shows the following reactions:

(i) It fumes in moist air.
(ii) The intensity of fumes increases when a rod diffed in ${NH}_{4}OH$ is brought near it.
(iii) An acidic solution of (X) on addition of ${NH}_{4}Cl$ and ${NH}_{4}OH$ gives a precipitate which dissolves in $NaOH$ solution.
(iv) An acidic solution of (X) does not give precipitate with $H_{2}S$. Compound (X) is identified as ${AlCl}_3$

If the given statement is true enter 1, else enter 0.

Answer 1

The inorganic Lewis acid (X) is ${AlCl}_3$
(i) It fumes in moist air as it absorbs moisture from the air and form HCl gas. ${AlCl}_3+H_{2}O⟶{Al\left(OH\right)}_3+3HCl$.
(ii) The intensity of fumes increases when a rod diffed in ${NH}_{4}OH$ is brought near it. Ammonia reacts with HCl to form dense white fumes of ammonium chloride.${NH}_3+HCl⟶\underset{whitefumes}{{NH}_{4}Cl}\downarrow$
(iii) An acidic solution of aluminum chloride on addition of ${NH}_{4}Cl$ and ${NH}_{4}OH$ gives white precipitate of aluminum hydroxide which dissolves in $NaOH$ solution forming sodium meta aluminate.
${AlCl}_3+{3NH}_{4}OH⟶\underset{white}{{Al\left(OH\right)}_3}\downarrow {3NH}_{4}Cl$
${Al\left(OH\right)}_3+NaOH⟶\underset{soluble}{{NaAlO}_2}+{2H}_{2}O$.
(iv) An acidic solution of aluminum chloride does not give precipitate with $H_{2}S$