Question

How does Changing Concentration affect EMF?

Answer 1

1. The moving of concentration cell takes place form the lower concentration cell to the higher concentration cell to maintain equilibrium,
2. For full cell reaction, it can be seen from Nerst equation:
3. $$\begin{gathered} \mathrm{A}\underset{}{\overset{}{\to }}\mathrm{B} \\ \mathrm{E}=\mathrm{E}-\frac{\mathrm{RT}}{\mathrm{nF}}\ln \left[\mathrm{B}/\mathrm{A}\right] \end{gathered}$$
4. The emf increases with the concentration of reactants relative to product and the cell become more spontaneous.
5. The emf decreases with the concentration of product increase relative to reactants.