Question

At 298 K, the standard reduction potentials for the following half-reactions are given. Which acts as an anode with others in an electrochemical cell?

$Z{n}^{+2}\left(aq\right)+2e^{-}\to Zn\left(s\right),$ -0.762 V

$C{r}^{+3}\left(aq\right)+3e^{-}\to Cr\left(s\right),$ -0.740 V

$2H^{+}\left(aq\right)+2e^{-}\to H_2\left(g\right),$ 0.000 V

$F{e}^{+3}\left(aq\right)+e^{-}\to F{e}^{2+}\left(aq\right),$ +0.762 V

• A. $Zn\left(s\right)$
• B. $H_2\left(g\right)$
• C. $Cr\left(s\right)$
• D. $F{e}^{2+}\left(aq\right)$

Answer 1

Answer: (A)

$E_{cell}=\text{SRP of cathode}-\text{SRP of anode}$