Question

An electrode is prepared by dipping a silver strip into a solution saturated with silver thiocyanate and containing $0.1MSC{N}^{-}$. The emf of the voltic cell constructed by connecting this electrode as the cathode to the standard hydrogen half cell, as the anode is 0.45V. The solubility of $AgSCNisx\times {10}^v$. Report your answer as (x - y)?
$[E_{A{g}^{+}/Ag}^{\circ }=0.8V]$

Answer 1

$AgSCN\rightleftharpoons A{g}^{+}+SC{N}^{-}$
S (S + 0.1)
$E_{cell}=E_{A{g}^{+}/Ag}^{\circ }-\frac{0.0591}{1}\log \frac{1}{\left[A{g}^{+}\right]}$
$0.45=0.8+0.0591\log \left[A{g}^{+}\right]$
$\left[A{g}^{+}\right]=1\times {10}^{-6}$
$\therefore Ksp=1\times {10}^{-6}\times {10}^{-1}=1\times {10}^{-7}$
$\therefore Ans=1-(-7)=8$