Redox Reactions And Electrochemistry Question 742
Question: Aluminium oxide may be electrolysed at 1000°C to furnish aluminium metal (At. Mass = 27 amu; 1 Faraday = 96,500 Coulombs). The cathode reaction is $ Al^{3}+3{e^{-}}\to Al{}^\circ $ To prepare 5.12kg of aluminium metal by this method would require [AIEEE 2005]
Options:
A) $ 5.49\times 10^{7}C $ of electricity
B) $ 1.83\times 10^{7}C $ of electricity
C) $ 5.49\times 10^{4}C $ of electricity
D) $ 5.49\times 10^{1}C $ of electricity
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Answer:
Correct Answer: A
Solution:
27 gm of Al is obtained by passing a current of 3 × 96500 C.
$ \because $ 1 gm of Al is obtained by passing a current of $ 3\times \frac{96500}{27}C. $ \ 5.12 × 103 gm of Al is obtained by passing a current of $ 3\times \frac{96500}{27}\times 5.12\times 1000 $ = 1.83 × 107 C × 3 = 5.49 × 107C.
BETA
