Question

The standard oxidation potentials of $Zn$ and $Ag$ in water at $25°C$ are
$Zn(s) \to Zn^{2+} + 2e [E° = 0.76 V]$
$Ag(s) \to Ag+ + e [E^{°} = -0.80 V]$
Which of the following reactions actually takes place?

• A. $Zn(r) + 2Ag^{+} (aq) \to Zn^{2+} + 2Ag(s)$
• B. $Zn^{2+} + 2Ag^{+} (s) \to 2Ag^{+} (aq) + Zn(s)$
• C. $Zn(s) + 2Ag(s) \to Zn^{2+} (aq) + Ag^+ (s)$
• D. $Zn^{2+} (aq) + Ag^{+} (aq) \to Zn(s) + Ag(s)$

Answer 1

Answer: (A)

$Zn(s) + 2Ag^{+} \to 2Ag + Zn^{2+}$
$E^{°} = 0.76 + 0.8 = 1.56\, V$