Question

If a $Z{n}^{2+}/Zn$ electrode is diluted $100$ times, then the emf will show: 

• (A) An increase of $59mV$
• (B) A decrease of $59mV$
• (C) An increase of $29.5mV$
• (D) A decrease of $29.5mV$

Answer 1

The Correct Option is B

Explanation:
We know,$E_{cell}=\frac{0.059}{2}\log \frac{1}{C}$where, $C=100$ times$E_{\text{cell }}=-\frac{0.059}{2}\log \frac{1}{100}$      $(\because \log \frac{1}{100}=-2)$$=-\frac{0.059}{2}\times -2$$=0.059V$$=59mV$Thus, if the $Z{n}^{2+}/Zn$ electrode is diluted to $100$ times than the emf is decrease of $59mV$.Hence, the correct option is (B).