Chromium metal is electroplated using an acidic solution containing CrO_{3} according to the following equation :

CrO_{3}(aq)+6H^{+}+6e^{-}\rightarrow Cr(s)+3H_{2}O

Calculate how many grams of chromium will be electroplated by 24,000 coulombs. How long will it take to electroplate 1·5 g chromium using 12·5 A current ?

[Atomic mass of Cr=52\; g\; mol^{-1},\; 1\; F=96500\; C\; mol^{-1} ]


 

 

 

 

 
 
 
 
 

Answers (1)
S Sumit

CrO_{3}(aq)+6H^{+}+6e^{-}\rightarrow Cr(s)+3H_{2}O

n\neq 6

Q=24000\; C

Q=n\times nfactor\times f

n=\frac{24000}{6\times 96500}

     =0.04145\; mol

Molar mass of Cr=52

\therefore 52\times 0.04145=2.155\; g

Charge =\frac{6\times 1.5}{52}\times 96500

        =12.5\times t=\frac{1.5}{52}\times 6\times 96500

    t=\frac{1.5\times 6\times 96500}{52\times 12.5}

        =1.336.15\; t

 

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