What is the `[OH^(-)]` in the final solution prepared by mixing `20.0 mL` of `0.050 M HCl` with `30.0 mL` of `0.10 M Ba(OH)_(2)`?

Options

A. `0.10 M`
B. `0.40 M`
C. `0.0050 M`
D. `0.12 M`

Answer

A

Explanation

Number of milleequivalent of `HCl`
`=20xx0.050xx1=1`
Number of millequivalent of `Ba(OH)_(2)`
`=2xx30xx0.1=6`
milliequivalent of `Ba(OH)_(2)`
`[OH^(-)]` of final solution `=` (milliequivalent of `HCl`)/(total volume)
`=(6-1)/(50)=0.1 M`