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Al(2)O(3) is reduced by electrolysis at ...

`Al_(2)O_(3)` is reduced by electrolysis at low potentials and high current. If `4.0 xx 10^(4)` amperes of currernt is passed through molten `Al_(2)O_(3)` for 6 hours, what mass of aluminium is produced? (Assume 100 % current efficiency, At. Mass of `Al = 27 u`)

A

`9.0 xx 10^(3)` g

B

`8.1 xx 10^(4)` g

C

`2.4 xx 10^(-4)`

D

`1.3 xx 10^(4)` g

Text Solution

Verified by Experts

The correct Answer is:
b
The reaction is `Al^(3+) + 3e^(-) to Al`
`E_(Al) =(At. Wt.)/3 = 27/3=9`
Now, `w=(Ei.t)/(96500)`
`=(9 xx 4 xx 10^(4) xx 6 xx 60 xx 60)/96500`
`=8.05 xx 10^(4) = 8.1 xx 10^(4)` g
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