When weak base solution `(50mL of 0.1 N NH_(4)OH)` is titrated with strong acid `(0.1N HCI)`, the `pH` of the solution initially decrease fast and then decreases slowely till near the equivalence point (as shown in figure). Which of the following is//are correct.

Options

A. The slow decrease of `pH` is due to the formation of an acidic buffer solution after the addition of some `HCI`.
B. The slope of shown graph will be minimum when `25mL` of `0.1N HCI` is added.
C. The slow decrease of `pH` is due to the formation of basic buffer solution.
D. The initial fast decrease in `pH` is due to fast consumption of `overset(Theta)OH` ions by `HCI`.

Answer

B, C, D

Explanation

(a) is wrong. For reaction of `S_(A)` with `S_(B)`, basic buffer is formed `beta` is maximum. When `pOH = pK_(b)`.
At `50%` neutralisation `(25 mL "of" 0.1 N HCI)`
Slope of the given graph will be least the buffer will have maximum buffer capacity