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JEE Main2014ChemistryRedox ReactionsActual

How many electrons are involved in the following redox reaction ? Cr 2 O 7 2 - + Fe 2 + + C 2 O 4 2 - → Cr 3 + + Fe 3 + + CO 2 (Unbalanced)

Options

  1. A6
  2. B5
  3. C3
  4. D4

Correct answer

A. 6

Step-by-step solution

[ F e 2 + + C 2 O 4 2 −     →     F e 3 + + 2 C O 2 + 3 e − ] × 2 ( o x i d a t i o n ) C r 2 O 7 2 − + 14 H + + 6 e −     →     2 C r 3 + + 7 H 2 O ( r e d u c t i o n ) _____________________________________________________ Cr 2 O 7 2 − + 2 Fe   2 + + 2 C 2 O 4 2 − + 14 H + → 2 Cr 3 + + 2 Fe 3 + + 4 CO 2 + 7 H 2 O Hence, total 6 electrons are involved in the net redox reaction to happen.

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