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Electrochemistry

Question
CBSEENCH12011241

A solution contains Fe2+ Fe3+, and I- ions. This solution was treated with iodine at 35o C.Eo for Fe3+/ Fe2+ is +0.77 V and Eo for I2/ 2 I- = 0.536 V. The favourable redox reaction is 

  • I2 will be reduced to I-

  • There will be No redox reaction

  • I- will be oxidised to I2

  • Fe2+ will be oxidised to Fe3+

Solution

C.

I- will be oxidised to I2

  2 space straight I to the power of minus space rightwards arrow space straight I subscript 2 space plus space 2 straight e to the power of minus space left parenthesis oxidation space half space minus space reaction right parenthesis
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space straight E subscript oxidation superscript straight o space equals space minus 0.536 space straight V

Fe to the power of 3 plus end exponent space plus space straight e to the power of minus space space rightwards arrow space Fe to the power of 2 plus end exponent space left parenthesis reduction space half space minus space reaction right parenthesis
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space straight E subscript reduction superscript straight o space equals negative space 0.77 space straight V
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space 2 Fe to the power of 3 plus end exponent space plus space 2 straight I to the power of minus space rightwards arrow space 2 space Fe to the power of 2 plus end exponent space plus space straight I subscript 2 semicolon
straight E to the power of straight o space equals space straight E subscript oxidation superscript straight o space plus space straight E subscript reduction superscript straight o
plus space ve
So comma space reaction space will space take space place.


plus space 2 space straight I to the power of minus space rightwards arrow space