Page 10 - Pharmaceutical Analytical Chemistry II - Pharm D- 02-06-07102
P. 10

Ecell = EAg ─ ESHE

The potential of SHE is assigned a value of 0.00 V at all temp

Ecell = EAg ─ 0.000 = EAg

Standard Electrode potential, E0

It is the electrode potential whenever the activities of reactants and

products of the half-reaction are all unity. The electrode in

question is connected as cathode and the standard hydrogen

electrode, SHE is connected as anode

Reactant/Product            Activity term, A          Standard state
                                                           activity
Gas                [A] = partial pressure in atm,
                   PA                               p = 1 atm
Soluble substance  (1 atm = 760 mm Hg)
Pure solid,        [A] = activity ≈ Molar conc., M  1M
Pure liquid,
Solvent            No term for A is included in
                   equation, represented as 1

Standard hydrogen reference electrode "SHE"

Consists of:

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