Question

If the aqueous solutions of the following salts $AgN{O}_3,FeC{l}_3,HfC{l}_4,ZnS{O}_4$ are electrolysed for 1 hour with $10$ ampere current, which solution will deposit the maximum mass of the metal at cathode?
The atomic weights are: $Fe=56u,Zn=65u,Ag=108u,Hf=178u$

• A. $HfC{l}_4$
• B. $FeC{l}_3$
• C. $ZnS{O}_4$
• D. $AgN{O}_3$

Answer 1

The correct option is D $AgN{O}_3$

By first law of electrolysis,
$W=\frac{E}{96500}\times Q$
Higher is the equivalent mass of the metal more will be the amount deposited at cathode.

Compound	Equivalent mass of metals
$ZnS{O}_4$	For $Zn$ $\frac{65}{2}=32.5$
$FeC{l}_3$	For $Fe$ $\frac{56}{3}=18.66$
$HfC{l}_4$	For $Hf$ $\frac{178}{4}=44.5$
$AgN{O}_3$	For $Ag$ $\frac{108}{1}=108$

$\therefore$
Silver will be deposited at the maximum amount at cathode.