\(\underset{C(1 -\alpha)}{CH_3COOH} \rightleftharpoons \underset{C\alpha}{CH_3COO^\ominus} + \underset{C\alpha}{H^+}\)
\(K_a = \frac{C^2\alpha^2}{C(1 - \alpha)}\)
\(K_a = \frac{C\alpha^2}{1 - \alpha}\)
∵ Acetic acid is very weak acid, so we can write 1 - α ≈ 1
∴ Ka = cα2
\(\alpha = \sqrt{\frac{K_a}C}\)
As we can see in the above relation degree of dissociation of Acetic acid depends on the concentration of acid and its dissociation constant.
As we know dissociation constant only depends on the temperature therefore, degree of dissociation also affected by temperature.
At constant temperature, when concentration of acid decreases the degree of dissociation of Acetic acid increases.
Hence, temperature and dilution of Acetic acid affect the degree of dissociation.