X and Y are the number of electrons involved, respectively during the oxidation of $\mathrm{I}^{-}$ to $\mathrm{I}_{2}$ and $\mathrm{S}^{2-}$ to S by acidified $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$. The value of $\mathrm{X}+\mathrm{Y}$ is ____.

JEE Main · 2026 · 24 Jan 2026 · Shift 1 · Redox Reactions and Electrochemistry

X and Y are the number of electrons involved, respectively during the oxidation of

I^{-}

I_{2}

and

S^{2 -}

to S by acidified

K_{2} Cr_{2} O_{7}

. The value of

X + Y

is ____.

Answer: 12

With acidified dichromate each

C r_{2} O_{7}^{2 -}

is reduced by gaining six electrons. For iodide,

C r_{2} O_{7}^{2 -} + 14 H^{+} + 6 I^{-} \to 2C r^{3 +} + 3 I_{2} + 7 H_{2} O

, so six electrons are transferred and

X = 6

. For sulphide,

C r_{2} O_{7}^{2 -} + 14 H^{+} + 3 S^{2 -} \to 2C r^{3 +} + 3S + 7 H_{2} O

, again six electrons, so

Y = 6

. The value of

X + Y

12

JEE Main · 2026 · 24 Jan 2026 · Shift 1 · Integer answer