Question

Calculate the mass of Ag deposited at cathode when a current of 2A was passed through a solution of $Ag{NO}_3$ for 15 min.
(Given : Molar mass of $Ag=108g{mol}^{-1}$ $1F=96500C{mol}^{-1}$).

• A. $3.015g$
• B. $2.015g$
• C. $4.2g$
• D. $3.1g$

Answer 1

Answer: (B)

$2.015g$

Given:

Molar Mass of Ag = 108 g/mol

$1F=96500Cmo{l}^{-1}$

Reaction at cathode = $Ag+e^{-}\to Ag\left(s\right)$

$w=Zlt$

Where, w = Mass deposited at cathode

Z = electrochemical constant

I = current

t = time

Now I = 2amp

$t=15min=15\times 60=900seconds$

Z = Eq. wt of substance $/96500=108/96500$

So,

$w=\frac{108}{96500}\times 900\times 2$

= $2.015g$