Question

An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to:
A. increase in ionic mobility of ions
B. $100\% $ ionization of electrolyte at normal dilution
C. increase in both i.e. number of ions and ionic mobility of ions
D. increase in number of ions

Answer 1

Hint: Equivalent Conductance (${\Lambda _e}$ ) is defined as the conductance (or conducting power) of all the ions(of a solution) produced by dissolving one gram equivalent of an electrolyte in a particular solution. Whereas conductance is the degree to which an object conducts electricity and is calculated as the ratio of the current which flows to the potential difference present. This is the reciprocal of the resistance, and is measured in siemens or mhos.

Complete step by step answer:
The equivalent conductance is defined as the net conductance of every ion that is produced from one gram equivalent of a given substance. Mathematically, it can be calculated using the following formula:
\[{\Lambda _e} = {\text{ }}k \times V\]
Where, the term denotes the volume (in $mL$ ) that contains one gram equivalent of the given electrolyte. The term denotes the specific conductivity of the electrolyte ions.
The above equation can also be written as:
\[{\Lambda _e} = {\text{ }}k \times \dfrac{{1000}}{C}\]
Thus, an increase in equivalent conductance of a strong electrolyte with dilution is mainly due to the increase in the mobility in the ions as increasing the volume of the electrolyte will increase the mobility of the ions.
The correct option is A. increase in ionic mobility of ions.

So, the correct answer is “Option A”.

Note:
Another term which is related to equivalent conductance is molar conductance. This can be defined as the net conductance of all the ions produced when one mole of an electrolyte undergoes complete dissociation into its constituent ions. The formula for molar conductance is quite similar to that of equivalent conductance, but it is denoted by the symbol .
$\mu = k \times V$
Where, the term $'V'$ denotes the volume (in $mL$ ) that contains one gram equivalent of the given electrolyte. The term denotes the specific conductivity of the electrolyte ions.