Question

The oxidation potentials of $Zn, Cu, Ag, H_{2}$ and Ni are $0.76, -0.34, -0.80,0.00,0.25$ volt, respectively. Which of the following reactions will provide maximum voltage?

• A. $Zn + Cu^{2+} \to Cu + Zn^{2+}$
• B. $Zn + 2Ag^{+} \to 2Ag + Zn^{2+}$
• C. $H_{2} + Cu^{2+} \to 2H^{+} + Cu$
• D. $H_{2} + Ni^{2+} \to 2H^{+} + Ni$

Answer 1

Answer: (B)

$E°_{cell} = 0.8 - ( - 0.76) = 1.56 V$
Maximum voltage is produced when electrode having minimum oxidation potential is made cathode and maximum oxidation potential is made anode.