JEE Chemistry 2024 Question with Solution

Given: Aluminium chloride is dissolved in acidified aqueous solution.

Find: The geometry of the ion formed in solution.

Aluminium chloride, $\text{AlCl}_3$, gives hydrated $\text{Al}^{3+}$ ions in aqueous acidic medium. The aluminium ion is surrounded by six water molecules to form

$$[\text{Al}(\text{H}_2\text{O})_6]^{3+}$$

Since the coordination number is $6$, the complex has octahedral geometry.

Therefore, the correct option is A. The ion formed has octahedral geometry.

Given: In acidified aqueous solution, aluminium chloride forms a hydrated complex.

Find: The geometry of that complex ion.

From the solution, the ion formed is

$$[\text{Al}(\text{H}_2\text{O})_6]^{3+}$$

Here, six water molecules act as ligands around the central aluminium ion. A six-coordinate complex characteristically adopts octahedral arrangement.

Hence, the geometry is octahedral.

Note: The solution mentions option C, but the worked explanation explicitly concludes Octahedral, which matches option A in the listed options. Therefore, the defensible correct answer is A.