In Bronsted acid base theory, acids are proton (H+) donors bases are proton (H+) acceptors.
At the reaction, CH3OH (methly alcohol) donates one H+ to OH- ions (hydroxide). So that OH- becomes H2O with an extra H atom. (+) charge neutralizes (-) charge of ion. Notice that H2O is neutral. Since CH3OH lose one positive H atom, it becomes CH3O-.
Donor is CH3OH, so it is the acid and its conjugate base is CH3O- Acceptor is OH-, so it the base and its conjugate acid is H2O.
