Question

The pH of solution in a cell : Reference electrode $||H_3{O}^{+}(?)H_2|Pt$ can be determined by using the formula $pH=-\frac{[E_{cell}+E_{ref}]}{0.059}$. However, the use of hydrogen electrode to determine pH is usually ignored. Which are the correct facts about this observation?

• A. The use of H-electrode hinders in the establishment of the equilibrium at the surface and the electrode no longer behaves reversibly
• B. The use of H-electrode is usually restricted if solution contains reducible materials
• C. The use of H-electrode is usually restricted as it is easily poisoned
• D. The use of quinhydrone electrode as electrode is usually preferred as reference electrode $||H_3{O}^{+},Q,Q{H}_2|Au$

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A The use of H-electrode hinders in the establishment of the equilibrium at the surface and the electrode no longer behaves reversibly
B The use of H-electrode is usually restricted if solution contains reducible materials
C The use of H-electrode is usually restricted as it is easily poisoned
D The use of quinhydrone electrode as electrode is usually preferred as reference electrode $||H_3{O}^{+},Q,Q{H}_2|Au$

A. The use of H-electrode hinders in the establishment of the equilibrium at the surface and the electrode no longer behaves reversibly.
Thus, the option A is correct.
B. The use of H-electrode is usually restricted if solution contains reducible materials. The reducible materials will affect the hydrogen ion concentration and hence, the pH of solution.
Hence, the option B is correct.
C. The use of H-electrode is usually restricted as it is easily poisoned. Poisoning will alter the electrode potential.
Hence, the option C is correct.
D. Due to above facts, the use of quinhydrone electrode as electrode is usually preferred as reference electrode. It is represented by the notation $||H_3^{+}O(?)Q,Q{H}_2|Au$.
Thus, the option D is correct.