Question

The standard electrode potential for Daniell cell is $1.1\, volt$. What is the standard Gibbs energy for the reaction?

• A. $ 212.3 \, kJ \, mol^{-1}$
• B. $ - 212.3 \, kJ \, mol^{-1}$
• C. $106.15 \, kJ \, mol^{-1}$
• D. $ -106.15 \, kJ \, mol^{-1}$

Answer 1

Answer: (B)

Net reaction occurring in a Daniell cell is
$ Zn_{(s)} + Cu^{2+}_{(aq)} \rightarrow Zn^{2+}_{(aq)} + Cu_{(s)}$
$\Delta = - nFE^\circ = -2 \times 69500 \times 1.1$
$ = -212300 \, J \, mol^{-1} = 212.3 \, kJ \, mol^{-1} $