Answer to Question #101511 in Physical Chemistry for Abhishek

Question

How can ionic product be determined using conductivity measurements? Explain.

Answer 1

$\Lambda_m=\Lambda^0_m -K$ $(c)^{1/2}$

where ${\displaystyle \Lambda _{m}^{0}}$ is known as the limiting molar conductivity, K is an empirical constant and c is the electrolyte concentration. (Limiting here means "at the limit of the infinite dilution".)

so $\alpha$ (dissociation constant) can be calculated by formula $\Lambda$ $_m/\Lambda_m^0$

let's us take a example :

AB(s) $\leftrightarrow$ A⁺(aq) + B⁺ (aq)

C 0 0 ......initial

C - C$\alpha$ C$\alpha$ C$\alpha$ .......final

so, Solubility product = [A⁺][B⁺] = C²*$\alpha^2$

where C is the concentration and $\alpha$ is the dissociation constant which can be calculated from the above formula.