Question

If the $Z{n}^{2+}/Zn$ eletrode is diluted to 100 times then the change in e.m.f

• A. increase of 59 mV
• B. decrease of 59 mV
• C. increase of 29.5 mV
• D. decrease of 29.5 mV

Answer 1

Answer: (A)

increase of 59 mV

Half cell reaction:

$Z{n}^{2+}+2e^{-}\to Zn$

Now,

$\Delta E_{cell}=-\frac{0.059}{n}\log \frac{1}{C}=-\frac{0.059}{2}\log \frac{1}{100}$

$\Delta E_{cell}=\frac{-0.059}{2}\times (-2)=0.059V=59mV$. ( increase)