The standard reduction potential for Cu 2 + /Cu is + 0.34 V . Calculate the reduction potential at pH = 14…

The standard reduction potential for Cu 2 + /Cu is +   0.34   V . Calculate the reduction potential at pH = 14 for the above couple. K sp  of  Cu OH 2 = 1 × 10 − 19
  1. - 0.22   V
  2. + 0.22 V
  3. - 0.44 V
  4. + 0.44 V

Solution

When p H = 14,  [   H + ] = 10 − 14 and [ O H − ] = 1  M

K s p = [ C u 2 + ] [ O H − ] 2 = 10 − 19

∴ [ C u 2 + ] = 10 − 19 [ O H − ] 2 = 10 − 19


The half cell reaction

C u 2 + + 2 e − → C u

E = E O − 0.059 2 log 1 [ C u 2 + ]

= 0.34 − 0.059 2 log 1 10 − 19 = − 0.22  V

 

Asked in: JEE-TOPICTESTS-CHEMISTRY

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