The standard reduction potential of `Cu^(+)//Cu` couple is 0.34 V at `25^(@)C` calculate the reduction potential at `pH=14` for this couple.
(Given `K_(sp),Cu(OH)_(2)=1.0xx10^(-19)`)

Options

A. `-0.22 V`
B. `-0.71 V`
C. `+0.22 V`
D. `+0.71 V`

Answer

A

Explanation

Since `pH = 14`
`rArr pOH =0 rArr [OH^(-)] = 1M`
`Cu(OH)_(2) `K_(aq) = [Cu^(2+)][OH]^(2)`
`10^(-19) =(Cu^(2+))^(2)`
`rArr Cu^(2+) + 2e^(-) to Cu`
`E_("cell") = 0.34 - 0.0591/2 log 1/(Cu^(2+))` `=0.34 -0.059/2 log 1/10^(-23) rArr 0.34 - 0.0591/2 log 10^(19)`
`=0.34 - 0.0591/2 xx 19 rArr E_("cell") = -0.22 V`