Consider the reaction given by $$\begin{array} { l }
M \stackrel { k _ { 1 } } { \longrightarrow } M _ { ads } ^ { + } + e ^ { - } \
\
M _ { a d s} ^ { + } \frac { k _ { 2 } } { \longleftarrow k _ { - 2 } } M _ { s o l } ^ { 2 + } + e ^ { - }
\end{array}$$ .
-In the same mechanism, the faradaic current is given by
A) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) \right]$$
B) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) + k _ { 2 } \theta - k _ { - 2 } ( 1 - \theta ) C _ { M _ { \mathbf { sol} } ^ { +2 } } \right]$$
C) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) - k _ { 2 } \theta + k _ { - 2 } ( 1 - \theta ) C _ { M _ { \mathbf { sol } } ^ { +2 } } \right]$$
D) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) + k _ { 2 } \theta + k _ { - 2 } ( 1 - \theta ) C _ { M _ { sol} ^ {{ +2 } } } \right]$$

Question

Consider the reaction given by $$\begin{array} { l } 
M \stackrel { k _ { 1 } } { \longrightarrow } M _ { ads } ^ { + } + e ^ { - } \
\
M _ { a d s} ^ { + } \frac { k _ { 2 } } { \longleftarrow k _ { - 2 } } M _ { s o l } ^ { 2 + } + e ^ { - }
\end{array}$$ .
-In the same mechanism, the faradaic current is given by
A) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) \right]$$
B) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) + k _ { 2 } \theta - k _ { - 2 } ( 1 - \theta ) C _ { M _ { \mathbf { sol} } ^ { +2 } } \right]$$
C) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) - k _ { 2 } \theta + k _ { - 2 } ( 1 - \theta ) C _ { M _ { \mathbf { sol } } ^ { +2 } } \right]$$
D) $$i _ { F } = F \left[ k _ { 1 } ( 1 - \theta ) + k _ { 2 } \theta + k _ { - 2 } ( 1 - \theta ) C _ { M _ { sol} ^ {{ +2 } } } \right]$$

Quizplus · Accepted Answer

The faradaic current, $i_F$, is proportional to the rate of the electrochemical reaction. The correct expression must account for the forward reaction rates ($k_1$ and $k_2$) and the backward reaction rate ($k_{-2}$), considering the surface coverage ($\theta$) and the concentration of $M_{sol}^{2+}$. Option B correctly combines these factors: $k_1(1-\theta)$ for the adsorption of $M$ (unoccupied sites), $k_2\theta$ for the formation of $M_{sol}^{2+}$ from $M_{ads}^+$, and $-k_{-2}(1-\theta)C_{M_{sol}^{+2}}$ for the reverse reaction, considering the concentration of $M_{sol}^{2+}$ and the availability of unoccupied sites ($1-\theta$).

Consider the Reaction Given By -In the Same Mechanism, the Faradaic Current Is Given

Consider the Reaction Given By
-In the Same Mechanism, the Faradaic Current Is Given