Question

19.5g CH3FCOOH is dissolved in 500g of water the depression in the freezing point observed is 1.0k calculate van't hoff factor and dissociation constant of the acid.

Answer 1

Solution.

$\Delta T = i \times K(cr) \times Cm$

$Cm = \frac{19.5}{78.04 \times 0.5} = 0.50 \ mol/kg$

$i = \frac{\Delta T}{K(cr) \times Cm} = 1.08$

$\alpha = \frac{i-1}{k-1} = 0.08$

$Ka = \frac{\alpha^2C}{1- \alpha}$

$Ka = 3.48 \times 10^{-3}$

Answer:

i = 1.08

$Ka = 3.48 \times 10^{-3}$