Question

How much time will it take for a uniform current of $6.00$A to deposit $78$g of gold from a solution of $AuC{l}_4^{-}$? What mass of chlorine gas will be formed simultaneously at the anode of the cell?
(Atomic mass of Au $=197$)

• A. t$=3010$sec, w$=35.50$g
• B. t$=20306$sec, w$=45.54$g
• C. t$=19500$sec, w$=54.5$g
• D. t$=19139.16$sec, w$=42.24$g

Answer 1

The correct option is D t$=19139.16$sec, w$=42.24$g

$A{u}^{3+}+3e^{-}⟶Au$

$197$ $g⟶3$ $F$ of charge

$78$ $g⟶\frac{3}{197}\times 78$ $F$ of charge

$\therefore \frac{3\times 78}{197}=\frac{charge}{96500}=\frac{6\times t}{96500}$

$t=19139$ $s$

Faraday of charge $=1.18$ $F$

$2C{l}^{⊝}⟶C{l}_2+2e^{-}$

$2$ $F⟶71$ $g$ of $C{l}_2$

$1.18⟶\frac{71}{2}\times 1.18=42.2$ $g$