Capillary Characteristics and the Factors Affecting Them:

From the Ilkovic equation it is seen that the diffusion current depends on m and t (together referred as capillary characteristics) and are therefore affected by their variations.  'm' is directly proportional and 't' is inversely proportional to the net pressure on the mercury drop.  Those effects are reported within terms of height of mercury column above the capillary tip.  Accordingly, m^2/3 t^1/6 is proportional to √h corr and i_d of the Ilkovic equation.

 id / √h = K where K is constant

id  = K ' ( m^2/3t^1/6) where K ' = 607 nD ^1/2 c

m α h

t α (1/h)

id =K'(h^2/3×h^-1/6)=K'(h^2/3-1/6)

=K'(h^(4-1)/6) = K' h^1/2

Id/√h =K'

Some deviation from this denotes that the current must be partly or wholly governed by the rate of some process other than the diffusion of electroactive substance to the electrode surface.

Table:  Effect of mercury pressure on 'm' and 't':

(Solution: 0.10M potassium nitrate, data secured at -1.0 V vs SCE)