In order to oxidise a mixture of 1 mole each of $\ce{FeC2O4}$, $\ce{Fe2(C2O4)3}$, $\ce{FeSO4}$ and $\ce{Fe2(SO4)3}$ in acidic medium, the number of moles of $\ce{KMnO4}$ required is:

JEE Main · 2026 · 04 Apr 2026 · Shift 1 · d and f Block Elements

In order to oxidise a mixture of 1 mole each of

FeC X_{2} O X_{4}

Fe X_{2} (C X_{2} O X_{4}) X_{3}

FeSO X_{4}

and

Fe X_{2} (SO X_{4}) X_{3}

in acidic medium, the number of moles of

KMnO X_{4}

required is:

Answer: (B)

In acidic medium each

MnO X_{4} X^{-}

accepts five electrons. The electrons released by one mole of each species are:

FeC X_{2} O X_{4}

gives

1

(

Fe X^{2 +} \to Fe X^{3 +}

)

+ 2

(

C X_{2} O X_{4} X^{2 -} \to 2 CO X_{2}

)

= 3

;

Fe X_{2} (C X_{2} O X_{4}) X_{3}

gives

0

from iron (already

+ 3

)

+ 6

from three oxalates

= 6

;

FeSO X_{4}

gives

1

;

Fe X_{2} (SO X_{4}) X_{3}

gives

0

. The total is

3 + 6 + 1 + 0 = 10

electron-equivalents, so moles of

KMnO X_{4} = \frac{10}{5} = 2

JEE Main · 2026 · 04 Apr 2026 · Shift 1 · Single correct option