Q. If the ${\mathrm{\Delta}G}^{{^\circ}}$ of Acell reaction, $AgCl\ + \ e^{-}\ \rightarrow \ {Ag}^{+}\ + \ {Cl}^{-}\ is\ - 21.20\ kJ;$ The standard emf of the cell is
A) 0.220 V
B) -0.220 V
C) 0.229 V
D) -0.110 V
Explanation
(a)
We know that, ${\mathrm{\Delta}G}^{{^\circ}}$ $= \ - nF\ .\ E^{{^\circ}}\$
Where, $n\ = 1$ (number of transferred electron in the cell reaction)
F =96500 C (Faraday’s constant)
$E^{{^\circ}}$ = ? (the standard electrode potential of cell)
${\mathrm{\Delta}G}^{{^\circ}}$ = - 21.20 kJ (standard free energy)
∴ -21.20 × 1000 J = - 1 × 96500 × $E^{{^\circ}}$
Or $E^{{^\circ}}$ = $\frac{21200}{96500}$ = 0.220 V
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.