Question

The $\left(\frac{\partial E}{\partial T}\right)_p$ of different types of half cells are as follows:

A	B	C	D
1 × 10-4	2 × 10-4	0.1 × 10-4	0.2 × 10-4

(Where E is the electromotive force)
Which of the above half cells would be preferred to be used as reference electrode?

• A. A
• B. B
• C. C
• D. D

Answer 1

Answer: (C)

C

Answer 2

A reference electrode is preferred when it exhibits minimal variation in electromotive force (EMF) with temperature. This characteristic allows the electrode to be used across a broader range of temperatures without deviating significantly from the standard value. Therefore, electrodes with lower rates of change in EMF with respect to temperature ($\frac{\partial E}{\partial T}$​ at constant pressure) are preferred for their stability across diverse temperature conditions.