Chromium metal can be plated out from an acidic solution containing `CrO_(3)` according to the following equation.
`CrO_(3)(aq)+6H^(+)(aq)+6e^(-)rarrCr(s)+3H_(2)O`
Calculate (i) How many grams of chromium will be plated out by 24,000 C and (ii) How long will it take to plate out 1.5g of chromium by using 12.5 current?

Explanation

Molar of Cr=52 g Equivalent mass of `Cr=52/6`
(i) Mass of Cr deposited on passing 24000 coulumbs `=24000/96500xx52/6g=2.115g`
(ii) Number of gram equivalent of `Cr=1.5/52xx6=9/52`
`implies` Coulumbs required for `1.5 g Cr=1.5/52xx6=9/52 implies `
`t=(9xx09500)/(52xx12.5)s=22.27 m `in