Question

19.5 g of CH₂FCOOH is dissolved in 500 g of water. The depression in the freezing point of water observed is 1.0°C. Calculate the van’t Hoff factor and dissociation constant of fluoroacetic acid.

Answer 1

It is given that:

We know that:

Therefore, observed molar mass of

The calculated molar mass of is:

Therefore, van’t Hoff factor,

Let α be the degree of dissociation of

Now, the value of K_a is given as:

Taking the volume of the solution as 500 mL, we have the concentration:

Therefore,