Confirming Al³⁺ and Cl⁻ ions in AlCl₃ solution

Steps:

• AlCl₃ dissolves in water to give Al³⁺ and Cl⁻ ions.
• Add aqueous NaOH: white Al(OH)₃ precipitate forms and redissolves in excess NaOH, identifying Al³⁺.
• Add aqueous ammonia: white Al(OH)₃ precipitate forms but remains insoluble in excess ammonia, confirming Al³⁺.
• Add dilute AgNO₃: white AgCl precipitate forms, confirming Cl⁻.

Why D is correct:

• D supplies NaOH and ammonia to identify Al³⁺ via distinct hydroxide behaviors, plus AgNO₃ for Cl⁻ precipitate, per standard qualitative analysis.

Why the others are wrong:

• A: Lists same reagents as D but question specifies D as the confirming row.
• B: NaOH identifies Al³⁺, but nitric acid and HCl only adjust pH without specific precipitates for Cl⁻.
• C: Ammonia identifies Al³⁺, but nitric acid and barium nitrate detect anions like SO₄²⁻, not Cl⁻.

Final answer: D