Question

Aluminium chloride in acidified aqueous solution forms an ion having geometry:

• A. Square planar
• B. Tetrahedral
• C. Octahedral
• D. Trigonal bipyramidal

Answer 1

The Correct Option is C

To ascertain the geometry of the ion formed upon dissolving aluminium chloride in an acidified aqueous solution, an understanding of the chemical process is required.

Key Concepts:

• Aluminium chloride (\(\text{AlCl}_3\)), a Lewis acid, exhibits high solubility in water.
• In aqueous solution, particularly in an acidic environment, the \(\text{Al}^{3+}\) ion undergoes hydration.
• The \(\text{Al}^{3+}\) ion in aqueous solution typically displays a coordination number of 6, coordinating with six water molecules.

This results in the formation of the complex ion \(\text{[Al(H}_2\text{O})_6]^{3+}\) in solution.

Geometry Determination:

• The spatial arrangement of these six water molecules around the central \(\text{Al}^{3+}\) ion dictates an octahedral geometry, a common characteristic of six-coordinate complexes.
• Octahedral geometry features a central atom at the octahedron's core, with ligands positioned at each of its six vertices.

Summary:

Based on the preceding chemical principles and deductions, the ion present in an acidified aqueous solution of aluminium chloride possesses an octahedral geometry.

Consequently, the definitive geometry is Octahedral.