Salts of weak bases = acidic solutions?

[Alison Le 2E]

Hello! Can someone help explain why salts of weak bases produce acidic solutions and salts of weak acids produce basic solutions? (Topic from the outline.) Thanks!

[RJ Lopez 2l]

A salt such as NH4Cl is composed of a parent acid HCl(strong acid) and parent base NH3 (weak base). When determining if salts are acidic or basic in a solution, you would need to determine the parent acid and bases by adding water. Generally speaking halogens are strong acids and group 1 hydroxides, alkaline earth metal hydroxides and group 1 and 2 oxides are strong bases.

[205678283]

A weak base on the reactant side of the equation will match up with a strong conjugate acid on the product side of the equation, and vise versa! They complement one another. So whichever one (acid or base) is strong on the reactant side ,will determine the acidity/pH of the end solution.

[005778617]

The way I'd like to think about this is

If you have the conjugate acid of a weak base, then the solution would become acidic. And if you have the conjugate base of a weak acid, then the solution would become acidic. Basically, if you have the conjugate __ (acid/base) of a weak ___ (acid/base), then the solution would be either the opposite of the weak __ (acidic or basic).

Hope this helps!

[Hudson2J]

If a strong acid is combined with a weak base, the salt will be acidic. On the other hand, if a strong base is combined with a weak acid, the salt will be basic. This is because the weak acid/base is not strong enough to completely neutralize the strong base/acid, so we have a non-neutral substance left over.