finding the conjugate base and acid of salts

Question

• State a reasonable salt that would be a conjugate for the acid or base listed below. The counter ion should be neutral.

1. Quinoline,C9H7N                 conjugate :
2. HPO4^2-                            conjugate:

Answer 1

First determine whether they are either acids or bases by using the listed Ka or Kb values for quinoline and HPO4^2-. You should notice that quinoline is base and HPO4^2- is an acid. Then imagine that each of the compounds dissociate. In solution quinoline would form a conjugate acid while HPO4^2- would form a conjugate base. In proposing a salt you need to make sure that the cation is neutral. An example of a neutral cation is Na+. All you need to do is to form a Na ion with either the conjugate acid or base.