Question

How much will the reduction potential of a hydrogen electrode change when its solution initially at pH $=$ 0 is neutralised to pH $=$ 7?

• A. Increases by $0.059V$
• B. Decreases by $0.059V$
• C. Increases by $0.41V$
• D. Decreases by $0.41V$

Answer 1

Answer: (D)

Decreases by $0.41V$

According to Nernst equations,

$E=E^o-\left(0.0591/n\right)logQ$

$E=E^o+\frac{0.059}{1}log{10}^{-7}$

$=E^o+\frac{0.059\times (-7)}{1}$

$=E^o-0.41V$

So, the correct option is $D$