A 2.5 gm impure sample containing weak monoacidic base (Mol. Wt = 45) is dissolved in 100 ml water and titrated with 0.5 M HCL when `((1)/(5))^(th)` of the base was neutralised the pH was found to be 9 and at equivalent point pH of solution is 4.5. Given : All data at `25^(@)C` & log2 = 0.3.
Select correct statement(s).

Options

A. `k_(b)` of base is less that `10^(6)`
B. Concentration of salt (C) at equivalent points is 100 ml
C. Volume of HCl is used at equivalent point is 100 ml
D. Weight percentage of base in given sample is 80%.

Answer

B, C