JEE Main · 2025 · 04 Apr 2025 · Shift 1 · d and f Block Elements

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KMnO₄ acts as an oxidising agent in acidic medium. 'X' is the difference between the oxidation states of Mn in reactant and product. 'Y' is the number of 'd' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of X+Y is ____.

Answer: 10

Solution

In acidic medium permanganate, with manganese in the

+ 7

state, is reduced to

M n^{2 +}

, so the change in oxidation state is

X = 7 - 2 = 5

. The acetate test with neutral ferric chloride gives, on boiling, a brown-red precipitate of basic ferric acetate in which iron is present as

F e^{3 +}

, a

3 d^{5}

ion, so the number of

d

electrons is

Y = 5

. Their sum is

X + Y = 5 + 5 = 10

JEE Main · 2025 · 04 Apr 2025 · Shift 1 · Integer answer

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