Question

In a cell that utilises the reaction \[\ce{Zn_{(s)} + 2H{^{+}_{(aq)}} -> Zn{^{2+}_{(aq)}} + H2_{(g)}}\] addition of H₂SO₄ to cathode compartment will ______.

Options

• lower the E and shift equilibrium to the left.

• lower the E and shift the equilibrium to the right.

• increase the E and shift the equilibrium to the right.

• increase the E and shift the equilibrium to the left.

Answer 1

In a cell that utilises the reaction \[\ce{Zn_{(s)} + 2H{^{+}_{(aq)}} -> Zn{^{2+}_{(aq)}} + H2_{(g)}}\] addition of H₂SO₄ to cathode compartment will increase the E and shift the equilibrium to the right.

Explanation:

\[\ce{Zn_{(s)} + 2H{^{+}_{(aq)}} -> Zn{^{2+}_{(aq)}} + H2_{(g)}}\]

The corresponding cell is:

\[\ce{E_{cell} = E{^{\circ}_{cell}} - \frac{0.0591}{n} log_10 \frac{[Zn^{2+} [pH_2]}{[H^{+}]^2}}\]

The addition of H₂SO₄ increases [H⁺]. This increases the value of E_cell and shifts the equilibrium to the right, as per Le Chatelier’s principle.