Question

A cell composed of a platinum indicator electrode and a silver-silver chloride reference electrode in a solution containing both Fe 2 + and Fe 3 + has a cell potential of 0.693 V. If the silver-silver chloride electrode is replaced with a saturated calomel electrode (SCE), what is the new cell potential?

Answer 1

0.639 V

Step-by-step explanation:

The volatge of the cell containing both Ag/AgCl reference electrode and

`Fe^(2+)/Fe^(3+)` electrode = 0.693 V

Thus,

`E_(cathod)-E_(anode) =0.693 V`

E_{anode}=0.197 V

Note: potential of the silver-silver chloride reference electrode (0.197 V)

⇒E_{Cthode}= 0.693+0.197 = 0.890V

To calculate the voltage of the cell containing both the calomel reference

electrode and
`Fe^(2+)/Fe^(3+)` electrode as follows

Voltage of the cell =
`E_(cathod)-E_(anode)`

E_{anode}= calomel electrode= 0.241 V

Voltage of the cell = 0.890-0.241 = 0.639 V

Therefore, the new volatge is = 0.639 V