Question

The negative $Zn$ pole of a Daniell cell, sending a constant current through a circuit, decreases in mass by $0.13\, g$ in $30\, minutes$. If the electrochemical equivalent of $Zn$ and $Cu$ are $32.5$ and $31.5$ respectively, the increase in the mass of the positive $Cu$ pole in this time is

• A. 0.180 g
• B. 0.141 g
• C. 0.126 g
• D. 0.242 g

Answer 1

Answer: (C)

0.126 g

Answer 2

$\frac{m_{Zn}}{m_{Cu}}=\frac{Z_{zx}}{Z_{cx}}$ I and t are same for both Cu and Zn electrodes $\frac{0.13}{m_{Cu}}=\frac{31.5}{32.5}$ $m_{Cu}=\frac{0.13\times32.5}{32.5}=0.126\,g.$