Question

what is the potential of hydrogen of electrode in volt having a solution of pH=4 at 25°C
​

Answer 1

Explanation:

0.236V

As we know that,

pH=−log[H

+

]

[H

+

]=10

−4

(∵pH=4)

Reaction at electrod-

H

+

+e

−

⟶

2

1

H

2

Now from nernst equation,

E

cell

=E

°

cell

−

n

0.059

log

[H

+

]

[H

2

]

Here,

E

°

cell

=0,n=1,P

H

2

=1atm

Therefore,

E

cell

=−

1

0.059

log

10

−4

1

⇒E

cell

=−0.059(−log10

−4

)

⇒E

cell

=0.059×(−4)=−0.236V