When weak base solution (50 ml of 0.1 `NH_(4)OH`) is titrated with strong acid 0.1 N HCl, the pH of solution initially decreases fast and then decreases slowly till near equivalence point (as shown in the fig.) which of the following is true?
A. The slow decrease of pH is due to formation of an acidic buffer solution after additio on some HCl.
B. The slope of shown pH graph will be minimum when 25 ml of 0.1 N HCl is added.
C. the slow decrease of pH is due to formation of a basic buffer solution.
D. The initial fast decreament in pH is due to fast consumption of free `OH^(-) ` ions by HCl
