Question

calculate pH of 0.1M CH3COOH of 100ml of that solution?

Answer 1

You need Ka (dissociation constant) for
CH3COOH.

Answer 2

then what must i do after i have the Ka of CH3COOH

Answer 3

Ka*[CH3COOH]/[A-]=[H3O+]
pH=-log[H3O+]
that's it :)

Answer 4

6.99