Answer to Question #103365 in Physical Chemistry for Akshay Kumar

Question

Define degree of ionisation of a weak electrolyte and discuss the factors affecting
it

Answer 1

Degree of ionization is the ratio of the number of ionized molecules and the number of molecules dissolved in water.It can be expressed as a fraction or in percentage.It is generally denoted by $\alpha$ .

For example:

$\ \ \ \$ $CH_3COOH(aq) \to CH_3COO^-+H^+$

$t=0\ \ \ \$ $\ \ c$ $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0$

$t=t\ \ \ \ \ \ \ \ \ \ \ c(1-\alpha)\ \ \ \ \ \ \ \ \ \ \ \ c\alpha\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ c\alpha$

where $\alpha$ is degree of ionization.

 Factors affecting degree of ionization:

$(a)$. More is the dilution,higher is the degree of ionization.

$(b).$ Temperature- Generally degree of ionization increases with increase in temperature.

$(c).$ More is the amount of solvent,more is the ionization.

$(d).$ Degree of ionization decreases in presence of a strong electrolyte having a common ion in accordance with Le-Chatlier principle.

$(e).$ Nature of solute