Electrochemistry


Ohm's Law
$$ v = IR $$ $$ R = \rho \frac{l}{a} $$ Where V is Potential difference, R is Resistance, I is current, ρ is specific resistance, l is lenght of conductor and a is the cross-section of conductor.

Conductance
$$ G = \frac{1}{R} $$ $$ \text {The specific conductance k =} \frac{1}{\rho} $$


$$ \text { Cell constant } \rho = \frac{l}{a} $$ $$ k = G. \sigma $$

Molar conductance
$$ \text {Molar conductance }A_{\,M} ( \Phi _{\,C}) = \frac{\text {1000 x k}}{\text{ C (or M)}} $$ where C is concentration of electrolyte in terms of molarity.

Equivelant conductance
$$ \text {Equivelant conductance }A_{\,M} (A _{\,C}) = \frac{\text {1000 x k}}{\text{ C (or N)}} $$ where C is concentration(normality). AM = AN x (n-factor) $$ A _{\,o} = \lim_{C \to 0} A _{\,C} $$ where Ao = equivalent conductance at infinite dilution.

Faraday's first law of electrolysis
$$ m = Zit $$ where m is mass of substance deposited, Z is electrochemical equivalent, i is current and t is time. $$ Z = \frac {\text{Atomic mass}}{\text{n x F}} $$

Faraday's second law of electrolysis
$$ \frac {m _{\,1}} {m _{\,1}} = \frac {E _{\,1}} {E _{\,1}} $$ where E is equivalent weight.