Question

Statement 1: $AlCl_{3}$ forms dimer $Al_{2}Cl_{6}$ in gaseous state but it dissolves in $H_{2}O$ forming $[Al(H_{2}O )_{6}]^{3+}$ and $3Cl^{-}$ ions.
Statement 2: Aqueous solution of $AlCl_{3}$ is acidic due to hydrolysis.

• A. If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
• B. Ifboth Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
• C. If Statement 1 is true but Statement 2 is false.
• D. If Statement 1 is false but Statement 2 is true.

Answer 1

Answer: (B)

Statement 1: In gaseous phase and in non-polar solvent like benzene $AlCl_{3}$ exists as dimer, $Al_{2}Cl_{6}.$ High enthalpy of hydration in water breaks the covalent dimer forming $[Al(H_{2}O)_{6}]^{3+}$ and $3Cl^{-}$
Statement 2: $AlCl_{3} + 3H_{2}O \to Al(OH)_{3} + 3HCl$