Processing math: 100%


1)

For the following electrochemical cell at 298 K,

Pt(s)|H2(g,1bar)|H+(aq,1M)

                                    ||M4+(aq),M2+(aq)|Pt(s)

Ecell=0.092 V

when[M2+(aq)][M4+(aq)]=10x

Given:  E0M4+/M2+=0.15V:

2.303RTF=0.059V

 The value of x is


A) -2

B) -1

C) 1

D) 2

Answer:

Option D

Explanation:

Oxidation at anode

H2(g)2H+(aq)+2e;E0SHE=0.00V

Reduction at cathode

M4+(aq)+2eM2+(aq):

E0M4+/M2+=0.151V

Net:M4+(aq)+H2(g)M2+(aq)+2H+(aq):

K=[M2+][H+]2[M4+]PH2(E0cell=0.151V)

K=[M2+][M4+]

Ecell=E0cell0.0592logK

0.092=0.1510.0592log[M2+][M4+]

0.059=0.0592log10x

log10x=2

x=2