An aqueous solution of an unknown sodium halide ( NaX ) is treated with a few drops of chlorine water, followed by the addition of a small amount of carbon tetrachloride ( CCl₄ ). Upon shaking the mixture vigorously and allowing it to settle, the lower organic layer is observed to turn violet. Identify the original sodium halide present in the aqueous solution and the chemical species responsible for the violet colou

Step-by-step solution

When chlorine water is added to an aqueous solution containing iodide ions, chlorine acts as a stronger oxidising agent and displaces iodine from the solution. The reaction is: Cl₂(aq) + 2NaI(aq) 2NaCl(aq) + I₂(aq) The liberated iodine ( I₂ ) is non-polar and preferentially dissolves in the non-polar organic solvent carbon tetrachloride ( CCl₄ ). Elemental iodine imparts a characteristic violet colour to the CCl₄ layer. Therefore, the original salt is NaI and the species responsible for the violet colour is I₂ . An