Redox Reactions And Electrochemistry Ques 594
Question: How many electrons would be required to deposit 6.35 g of copper at the cathode during the electrolysis of an aqueous solution of copper sulphate- (Atomic mass of copper $ =63.5u,N_{A} $ = Avogadro’s constant):
Options:
A) $ \frac{N_{A}}{20} $
B) $ \frac{N_{A}}{10} $
C) $ \frac{N_{A}}{5} $
D) $ \frac{N_{A}}{2} $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ Cu\xrightarrow{{}}C{u^{++}}+2{e^{-}} $ i.e, to deposit 1 mole of Cu at cathode from $ C{u^{2+}}{SO_4^{2-}}^{~} $ solution = 2
moles of electrons are required i.e. To deposit $ 6.35g=\frac{6.35}{63.5}\times 2=\frac{2}{10}=\frac{1}{5}moles $
Thus total no. of electrons required $ =\frac{N _{A}}{5} $
