Q. A copper and a chromium voltmeter are connected in series with a battery. It found that in half an hour $0.475\ g$ of copper and $0.130\ g$ of chromium have been deposited. The ECE ratio of copper and chromium is
A) 0.274
B) 0.523
C) 3.65
D) 1.85
Explanation
(c) According to Faraday’s first law of electrolysis is
$m = zIt$
where$\ z$ is the electrochemical equivalent of the substance
As voltameters are connected in series, same current will pass through them for same time
$\therefore\frac{m_{Cu}}{m_{Cr}} = \frac{z_{Cu}}{z_{Cr}}\ or\ \frac{z_{Cu}}{z_{Cr}} = \frac{m_{Cu}}{m_{Cr}} = \frac{0.475}{0.130} = 3.65$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.