The pH of a buffer solution remains almost unchanged even after dilute- explain.

Explanation

Let buffer solution that consists of a weak acid (HX) and its salt (MX). For this buffer, `pH=pK_(a)+"log"(["salt"])/(["acid"])`
At a certain temperature, the value of `pK_(a)` is constant. Hence, at a given temperature, pH of a buffer solution depends upon the ratio of the molar concentrations of the salt to the acid in the solution. as the solution is diluted, this ratio remains the same. as a result, pH of the solution remains unaltered.