Question

For a cell reaction: $M_{\left(aq\right)}^{H+}+n{e}^{-}\to M_{\left(s\right)}$, the Nernst equation for electrode potential at any concentration measured with request to standard hydrogen electrode is represented as :

• A. $E_{\left(M^{n+}/M\right)}=E_{\left(M^{n+}/M\right)}^o-\frac{RT}{nF}1n\frac{1}{\left[M^{n+}\right]}$
• B. $E_{\left(M/M^{n+}\right)}=E_{\left(M/M^{n+}\right)}^o-\frac{RT}{nF}1n\frac{\left[M^{n+}\right]}{\left[M\right]}$
• C. $E_{\left(M^{n+}/M\right)}=E_{\left(M^{n+}/M\right)}^o-\frac{RT}{nF}log\frac{1}{\left[M\right]}$
• D. $E_{\left(M^{n+}/M\right)}=E_{\left(M^{n+}/M\right)}^o-\frac{RT}{nF}1n\left[M^{n+}\right]$

Answer 1

Answer: (A)

$E_{\left(M^{n+}/M\right)}=E_{\left(M^{n+}/M\right)}^o-\frac{RT}{nF}1n\frac{1}{\left[M^{n+}\right]}$

Nernst equation is,

$E_{cell}=E_{cell}^0-\frac{RT}{nF}lnQ$

where, Q is the reaction quotient of the reaction

As, $\left[M_{(}{s}_{)}\right]=1$

We get,

$E_{M^{n+}/M}=E_{M^{n+}/M}^0-\frac{RT}{nF}ln\frac{1}{M^{n+}}$