Cd amalgam is prepared by electrolysis of a solution of `CaCl_2` using a mercury cathode. Current of how much ampere must be passed for 100 seconds in order to prepare 20% Cd-Hg amalgam on a cathode of 2 g mercury? (At. wt. of Cd = 112.40)

Options

A. 34.32 ampere
B. 8.58 ampere
C. 4.29 ampere
D. 17.16 ampere

Answer

B

Explanation

20% Cd-Hg amalgam means 80 g Hg has 20 g Cd.
`therefore` 2 g Hg require= `20/80xx2` =0.5 g Cd
`Cd^(2+)2e^(-)toCd`
Eq. wt. of Cd =`112.4/2`
Applying, w= `ZxxIxxt,Z=(Eq.wt.)/96500`
`I=0.5xx96500xx2/112.4xx1/100 =8.58` ampere