Question

Explain (Definition and Formula):
(i) Kohlrausch's Law, (ii) Faraday's first law of electrolysis.

Answer 1

(i) Kohlrausch's Law: It is proposed by kohlrausch in 1876. "At infinite dilution the molar conductivity of the electrolyte at infinite dilution is the sum of the ionic conductivities of cations and anions, this is called kohlrausch's law".
Mathematically
${\lambda }_m^{\infty }=x{\lambda }_c^{\infty }+y{\lambda }_c^{\infty }$
${\lambda }_m^{\infty }=$ molar conductivity of electrolyte
${\lambda }_a^{\infty }=$ ionic conductivity of anion
${\lambda }_c^{\infty }=$ ionic conductivity of cation
$x=$ number of anions
$y=$ number of cations
(ii) Faraday's first law of electrolysis: "The weight of any substance deposited or liberated at electrode is directly proportional to the quantity of electricity passed".
$W\propto Q$
$Q=It$
$W=Zit$
where $W=$ Weight of substance
$Z=$ Electrochemical equivalence
$I=$ Current in ampere
$t=$ Time in second