Question

The solubility of iodine in water increases in the presence of

• A. Alcohol
• B. Chloroform
• C. Sodium hydroxide
• D. Potassium iodide

Answer 1

Answer: (D)

Iodine has the least affinity for water and is only slightly soluble in it. However, it dissolves in $10\%$ aq. solution of $KI$ due to the formation of a complex ion i.e. $I_3^{-}$
$I_2+KI\rightleftharpoons K{I}_3$ or $I_2+I^{-}\rightleftharpoons I_3^{-}$ (complex ion)