Redox Reactions And Electrochemistry Ques 636
Question: How long a current of 3 amperes has to be passed through a solution of $ AgNO_3 $ to coat a metal surface of $ 80cm^{2} $ and 0.005 mm thick layer. Density of Ag is $ 10.5g,c{m^{-3}} $
Options:
A) 125.1 seconds
B) 12.5 seconds
C) 155.2 seconds
D) 200 seconds
Show Answer
Answer:
Correct Answer: A
Solution:
[a] $ Volume=Area\times thickness $ $ Mass=Volume\times density $
$ \therefore $ Mass of Ag to be deposited $ =\frac{80\times 0.005}{10}\times 10.5=0.42g $ $ Amountdeposited=\frac{i\times t\times E.wt}{96500} $
$ \therefore 0.42=\frac{108\times 3\times t}{98500}\therefore t=125.1,seconds $
