Question

A layer of 0.25 mm thick chromium metal is to be electroplated on the rims of autovehicle with a total area of 32 $m^{2}$ from a solution of $CrO_{4}^{2 -}$ . What amount of electric current is required for electroplating the rims in 60 sec? The density of chromium metal is 7.2 g/cc.

• A. $4.9\times 10^{3}$ A
• B. $1.78\times 10^{3}$ A
• C. $5.3\times 10^{4}$ A
• D. $10.69\times 10^{6}$ A

Answer 1

Answer: (D)

Volume of coated lay = Area $\times $ thickness
$=32\times 10^{4}\times 0.025$
$=8000 \, cm^{3}$
Mass of chromium deposited = volume $\times $ density
$=8000\times 7.2$
$=57600$ g
$W=\frac{I t E}{96500}$
$57600=\frac{I \times 60 \times \left(\right. 52 / 6 \left.\right)}{96500}$
$I=10.69\times 10^{6}$ amp.