Question

Find dissociation constant of e thanoic acid having concentration 0.2M and degree of dissociation 50%

Answer 1

Let's call CH3COOH just HAc.
It is dissociates 50%, that means it starts at 0.2M and ends up at 0.1M with the products 0.1M

.........HAc --> H^+ + Ac^-
I........0.2.....0......0
C....-0.5*0.2...0.1.....0.1
E.......0.1.....0.1.....0.1

Plug this into the Ka expression but something is missing here because Kd for HAc is about 1.8E-5.

Ka =