Question

What is standard Gibbs free energy of reaction?
What is standard gibbs free energy of rxn
$Zn ( s )+ Cu ^{2+} \rightarrow Zn ^{2+}+ Cu ( s )$
Given $E ^{\circ} Zn ^{2+} / Zn =-0.74 \& E ^{\circ} Cu ^{2+} / Cu =0.36$

• A. 300 kJ
• B. -212.3 kJ
• C. -200 kJ
• D. 515 kJ

Answer 1

Answer: (B)

$E _{\text {cell }}^{o}= E _{\text {red }}^{o}= E _{\text {oxid }}^{o}$
$=0.36+0.74=1.10 V$
$\Delta G ^{0}=- nFE ^{\circ}$
$=-2 \times 96500 \times 1.10 J =212.3 kJ$