The ionic product of water at 298 K is `10^(-14) M^(2)` . The standard emf of the cell producing the reaction `H^(+)(aq)+OH^(-)(aq)rarr H_(2)O(l)` will be

Options

A. `0.723 V`
B. `-0.723 V`
C. `0.82 V`
D. `-0.82 V`

Answer

D

Explanation

The equilibrium constant of the reaction `H^(+) (aq)+OH^(+)(aq)rarrH_(2)O(1)`
since `triangleG^(@)=nFE^(@)=-RT In k^(@)` we have
`E^(@)=(RTIn k^(@))/(nF)=log k^(2)=(0.059 v)log (55.56xx10^(-14))=-0.723 V`