Weak Acid & Base Problem

[Justin Shafa 2E]

When given both a weak acid and weak base in a problem, how do we know which is the conjugate of the other and which one we use on the reactants side of the reaction?

[George]

I would assume that the problem would direct you in a manner that you would know. Just like in the practice problems

[005995461]

When given both a weak acid and weak base in a problem, how do we know which is the conjugate of the other and which one we use on the reactants side of the reaction?

The conjugate acid of the weak base would have the chemical formula of the weak base with an extra hydrogen and a neutral charge (unless it's NH3, in which case the conjugate acid would have a positive charge). It's vice versa for the conjugate base of the weak acid. If a strong acid and a base react, it would result in a salt + H2O.