100 ml solution having 0.2 M HA (weak acid, `K_(a), = 1.0x10^(-5) )` and 0.2 N NaA, 200 ml of 0.1 M NaOH has been added. Furthermore, diluted to IL. Which of the following statement is correct?

Options

A. Initially, the solution has pH equal to 5, that is before addition of NaOH
B. In the final solution, the concentration of `[OH^(-)]` is `10^(-9)` M.
C. After the addition of NaOH, the pH of solution increase by four units.
D. After the addition of base, the solution losses buffering action and can be restored after the addition of acid.

Answer

B