JEE Main 2026 Jan 23 Shift 2, Chemistry Q17: Oxidation and Reduction

JEE Main2026Jan 23, Shift 2Chemistry

The oxidation state of chromium in the final product formed in the reaction between KI and acidified $K_{2} C r_{2} O_{7}$ solution is:

Solution

Acidified dichromate oxidises iodide to iodine and is itself reduced:

$K_{2} C r_{2} O_{7} + K I H^{+} I_{2} + C r^{3 +}$

Chromium goes from $+ 6$ in $C r_{2} O_{7}^{2 -}$ to $+ 3$ in $C r^{3 +}$ in the final product.

Concept behind this question

Concept-wise practice with instant solutions on Fundamenthol.