Question

A cell contains two hydrogen electrodes. The negative electrode is in contact with a solution of ${10}^{-6}$ M hydrogen ions. The $EMF$ of the cell is $0.118V$ at ${25}^{\circ }C$. The concentration of hydrogen ions at the positive electrode is:

• A. ${10}^{-4}M$
• B. ${10}^{-3}M$
• C. ${10}^{-1}M$
• D. $Noneofthese$

Answer 1

The correct option is A ${10}^{-4}M$

$E_{c}ell=-0.059(p{H}_c-p{H}_a)$

$0.118V$ = $-0.059$ $(p{H}_c-6)$

$\therefore p{H}_c=\frac{-0.118}{0.059}+6$

$=-2+6=4$

$\therefore [H^{\oplus }{]}_c={10}^{-4}M$