Q. For Acell given below, $Ag\ |\ {Ag}^{+}\ ||\ {Cu}^{2 +}\ |\ Cu$ - + ${Ag}^{+}\ + \ e^{-}\ \ \longrightarrow \ \ Ag,\ \ \ \ \ \ E^{{^\circ}}\ = \ x$ ${Cu}^{2 +}\ + \ {2e}^{-}\ \ \longrightarrow \ \ Cu,\ \ \ \ \ \ E^{{^\circ}}\ = \ y$ $E_{cell}^{{^\circ}}$ is
A) $x\ + \ 2y$
B) $2x\ + \ y$
C) $y\ –\ x$
D) $y\ –\ 2x$
Explanation
(c)
At LHS (oxidation) $2\ \times \ (Ag\ \rightarrow \ {Ag}^{+}\ + \ e^{-}\ ),\ \ E_{oxi}^{{^\circ}}\ = \ - x\$
At RHS (reduction)
${Cu}^{2 +} + \ {2e}^{-}\ \rightarrow Cu,\ \ \ \ \ \ \ \ \ \ \ \ E_{red}^{{^\circ}}\ = \ + \ y$
[table] $2Ag + \ {Cu}^{2 +}\ \rightarrow Cu + \ {2Ag}^{+}\ ,\ E_{cell}^{{^\circ}}\ = (y - x)$ [/table]
Note $E^{{^\circ}}$ values remain constant when half – cell equation is multiplied / divided.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.