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Electrochemistry

Question
CBSEENCH12011094

When 0.1 mol MnO42- is oxidised, the quantity of electricity required to completely oxidise MnO42- to MnO42- is

  • 95600C

  • 2 x 96500C

  • 9650 C

  • 96.50 C

Solution

C.

9650 C

stack MnO subscript 7 superscript 2 minus end superscript with plus 7 below space rightwards harpoon over leftwards harpoon with straight i space straight e to the power of minus space left square bracket space 1 equals space straight F right square bracket on top space stack MnO subscript 4 superscript minus with plus 6 below
As per the equation, for 1 mole of MnO42-, 1F of electricity is required. Thus, for 0.1 mole of MnO4-, 0.1 F of electricity is required.
Since, 1 F = 96500 C
0.1 F = 0.1 x  96500 C
= 9650 C
Hence, 9650 C of electricity is required to completely oxidise MnO42- to MnO4-