Q. An electric current is passed through silver nitrate solution using silver electrodes. 10.79 g of silver was found to be deposited on the cathode. If the same amount of electricity is passed through copper sulphate solution using copper electrodes, the weight of copper deposited on the cathode is
A) 1.6 g
B) 2.3 g
C) 3.2 g
D) 6.4 g
Explanation
(c)
Number of equivalents of silver formed
= number of equivalents of copper formed
In ${AgNO}_{3},\$Ag is in$\ + 1$ oxidation state
In ${CuSO}_{4},\$Cu is in$\ + 2$ oxidation state
Equivalent weight of $Ag = \frac{108}{1} = 108$
Equivalent weight of $Cu = \frac{63.6}{2} = 31.8$
$\frac{w_{1}}{w_{2}} = \frac{E_{1}}{E_{2}}$
$\therefore\frac{10.79}{w_{Cu}} = \frac{108}{31.8}$
Or$\ \ w_{Cu} = \frac{10.79 \times 31.8}{108} = 3.2\ g$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.