Question

Calculate molar concentration of formic acid solution if degree of dissociation is 4% K(HCOOH)=2.10^_4

Answer 1

Answer: The molar concentration of formic acid solution is 0.12 M

Explanation:

$HCOOH\rightarrow HCOO^-+H^+$

 cM                0             0

$c-c\alpha$      $c\alpha$    $c\alpha$  

So dissociation constant will be:

$K_a=\frac{(c\alpha)^{2}}{c-c\alpha}$

Give c= ? and $\alpha$ = $\frac{4}{100}=0.04$

$2\times 10^{-4}=\frac{(c\times 0.04)^2}{(c-c\times 0.04)}$

On solving for c we get:

$c=0.12M$

Thus molar concentration of formic acid solution is 0.12 M