Question

$108g$ fairly concentrated solution of $AgN{O}_3$ is electrolyzed using $0.1$ F of electricity. The weight of resulting solution is: [At. wt of $Ag=108$]

• A. $94g$
• B. $11.6g$
• C. $96.4g$
• D. None of these

Answer 1

Answer: (C)

$96.4g$

If $AgN{O}_3$ solution is electrolyzed,

Reaction at cathode,

$A{g}^{+}+e^{-}\to Ag$
Reaction at anode,
$4O{H}^{-}\to O_2+2H_{2}O+4e^{-}$

$1F$ electricity produce $1molAg$

$0.1F$ electricity produce $0.1molAg$

Weight of $Ag$ produce $=0.1\times 108=10.8$

If electricity produced by consumption of $4molO{H}^{-}$

$4F$ electricity evolves 1 mol of $O_2$ ar the anode reaction, that is $32$ g of oxygen gas.

$0.1F$ electricity produce = $0.1\times \left(32/4\right)=0.8$ g

$0.1mol$ Oxygen also get out of solution

so remaining solution $=108-10.8-0.8$

$=96.4g$
Option C is correct