$\mathrm{KMnO}_{4}$ is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute $\mathrm{H}_{2} \mathrm{SO}_{4}$. Number of water molecules produced for 2 molecules of $\mathrm{KMnO}_{4}$ is $\_\_\_\_$.

JEE Main · 2023 · 13 Apr 2023 · Shift 1 · Redox Reactions and Electrochemistry

KMnO_{4}

is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute

H_{2} SO_{4}

. Number of water molecules produced for 2 molecules of

KMnO_{4}

____

Answer: 68

Solution

In acidic medium permanganate oxidises the ferrous ions supplied by the hexahydrate salt. The balanced equation is

10 FeS O_{4} \cdot (N H_{4})_{2} S O_{4} \cdot 6 H_{2} O + 2 KMn O_{4} + 8 H_{2} S O_{4} \to 5 F e_{2} (S O_{4})_{3} + 2 MnS O_{4} + K_{2} S O_{4} + 10 (N H_{4})_{2} S O_{4} + 68 H_{2} O

. Reduction of the two permanganate ions releases eight water molecules, and the ten molecules of the hexahydrate salt release a further sixty water molecules of crystallisation. For two molecules of potassium permanganate the number of water molecules produced is sixty-eight.

JEE Main · 2023 · 13 Apr 2023 · Shift 1 · Integer answer

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JEE Main · 2023 · 13 Apr 2023 · Shift 1 · Redox Reactions and Electrochemistry

Solution

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