One Faraday of electricity is passed through molten `Al_(2)O_(3), `aqueous solution of `CuSO_(4)` and molten NaCl taken in three different electrolytic cells connected in series. The mole ratio of AI, Cu and Na deposited at the respective cathode is

Options

A. `2:3:6`
B. `6:2:3`
C. `6:3:2`
D. `1:2:3`

Answer

A

Explanation

The charge carried by 1 mole of electrons is one faraday. Thus for a reaction
`M^(n+) +nc ^(-) to M`
`nF=1` mole of M
`{:(Al^(3+)+3e^(-) to Al),(3F " ""1mole"),(IF " ""1/3mole"):} `
`{:(Cu^(2+) +2c^(-) to Cu),(2F " ""1mole"),(IF " ""1mole"):}`
`{:(Na^(+)+e ^(-) to Na),(IF " ""mole"):}`
The mole ration of Al, Cu and Na deposited at eh respectivecat ode is `1/3. 1/2: 1 sigma 2:3:6`