Question

In buffer solution, the strong base why used not weak base?

Answer 1

Answer:

The idea of a buffer solution is that it presents a high concentration of both and acid and a basis coexisting in equilibrium. That way, if we dilute an new acid, the basis will protonate itself and if we dilute a basis the acid will deprotonate, always neutralizing each other and therefore the effect in the pH is negligible.

A strong acid cannot do this, because it cannot coexist in equilibrium with is conjugate basis. When you dilute a strong acid it deprotonate fully to form a proton and its conjugate basis. If we dilute a new acid, there will be no basis capable of protonating itself, nor there will be any acid left for when we dilute a new basis.

So all buffers are created by mixing equal high concentrations of an weak acid and its conjugate basis. This is the condition at which the buffer power is maximum, keeping the system stable at a pH equal to the pKa of the acid.