Q.

MX is a sparingly soluble salt that follows the given solubility equilibrium at 298 K.

MX(s)M+(aq)+X- (aq);  Ksp=10-10

If the standard reduction potential for M+(aq)+e-M(s) is (EM+/M)=0.79 V, then the value of the standard reduction potential for the metal/metal insoluble salt electrode EX-/MX(s)/M is ___________________mV. (nearest integer).      

[Given: 2.303RTF=0.059 V]       [2026]


Ans.

(200)

EX-/MX(s)/M=EM+/M+0.0591nlogKsp

=0.79+0.0591log(10-10)

=0.79-0.59

=0.20 V=200 mV