The mass of any substance liberated at the electrode in electrolysis is proportional to the mass of a given substance liberated when unit a quantity of charge passes through the electrolyte
Formula 1
G = g.I.t
Where:
G is the mass of deposited substance in milligrams (mg)
g is the chemical equivalent of the involved substance in mg/As
I is the amount of current flowing between electrodes in amperes (A)
T is the electrolysis time in seconds (s)
Electrochemical Equivalents of Some Substances
| Íon | G (mg/As) |
| H+ | 1,0104 |
| O- | 0,0829 |
| Al+++ | 0,936 |
| OH- | 0,172 |
| Fe+++ | 0,1930 |
| Ca++ | 0,2077 |
| Na+ | 0,2388 |
| Fe++ | 0,2895 |
| C03-- | 0,3108 |
| Cu++ | 0,3297 |
| Zn++ | 0,3387 |
| Cl- | 0,3672 |
| SO4- - | 0,4975 |
| Cu+ | 0,6590 |
| Ag+ | 1,118 |
Derivated Formulas:
Formula 2
I = G / (g . t)
Formula 3
t = G / (g . I)
Application Example:
Calculate the mass of silver (Ag) deposited in na electrolysis process when a 2 A current flows for 10 minutes.
Data:
G = 1,118 mg/As
I = 2 A
T = 10 minutes = 600 seconds
Applying formula 1:
G = 1,118 x 2 x 600 = 1 341 mg ou 1,341 g
