A current of `10A` is employed to plate nickel in `NiSO_(4)` bath. The current efficiency with respect to `Ni` plating is `60%`.
`a.` How many grams of `Ni` is plated on the cathode per hour ?
`b.` What is the thickness of the plating if the cathode consists of a sheet of metal `4.0 cm^(2)` which is coated on both faces ?
`c.` What is the volume of `H_(2)(STP)` evolved during above electrolysis ?

Explanation

At cathode`:Ni^(2+)+2e^(-)rarr Ni`
`2H^(o+)+2e^(-)rarr H_(2)`
Both reactions `(` reduction `)` occur simultaneously in the given case.
Number of Faradays
`=(It)/(96500)=(10xx60xx60)/(96500)F=0.373F`
`2F=1mol Ni`
`=0.373F=(0.373)/(2)xx59g=11.00g`
`a.` For `60%` efficiency , weight of `Ni` plated
`=60)/(100)xx11=6.6g Ni`
`b.` Mass `=` Area`xx` Thickness`xx` Density
`6.6=4xx(2t)xx1.25 " "(` Here `t=`thickness `)`
`impliest=(6.6)/(10)=0.66cm=6.6mm`
`c.` `2F-=1 mol =22400mL H_(2)`
`0.373F=(22400xx0.373)/(2)=4177.6mL-=4.178L`