In an industrial electrolytic cell it is desired to produce `36 Kg` of magnesium metal per hour. The current required will be

Options

A. `8.04 xx 10^(5) amp`
B. `8.04 xx 10^(3) amp`
C. `8.04 xx 10^(4) amp`
D. `8.04 xx 10^(2) amp`

Answer

C

Explanation

`Mg^(2+)+2e^(-) rarr Mg`
According to Faraday's laws
`(m)/(E) = (It)/(F)`
or `I = (m)/(E) xx (F)/(t)`
`= (36000 g)/(12 "g eq."^(-1)) xx (96,500 C eq.^(-1))/(60 xx 620 sec s)`
`= 80416` ampers
`= 8.04 xx 10^(4)` ampers
Note that equivalent mass `= ("atomic mass")/("change in oxidation number")`
In the electrode reaction, oxidation number of `Mg` is changing from `+2` to `0`.