Which of the following statement `is//are` correct?
`20.0 mL` of `6.0 M HCl` is mixed with `50.0 mL` of `2.0 M Ba(OH)_(2)`, and `30 mL` of water is added.

Options

A. The concentration of `overset(ɵ)(OH)` remaining in solution is `0.8 M`.
B. The concentration of `Cl^(ɵ)` remaining in solution is `1.2 M`
C. The concentration of `Ba^(2+)` remaining in solution is `1.0 M`
D. 80 mmols of `overset(ɵ)(OH)` is in excess.

Answer

A, B, C, D

Explanation

mmoles of `HCl implies 20 xx 6 = 120 implies 120 "mmol" H^(o+) + 120 "mmol" Cl^(ɵ)`
mmoles of `Ba (OH)_(2) implies 50 xx 2 implies 100 "mmol"`
`Ba^(2+) + 200 "mmol" overset(ɵ)(O)H`
`H^(o+) + overset(ɵ)(O)H rarr H_(2) O`
Total volume `= 20 + 50 + 30 = 100 mL`
a. `:. [overset(ɵ)(O)H] = ((200 - 120 )"mmol")/(100 mL) = 0.8 M`
b. `[Cl^(ɵ)] = (120 "mmol")/(100 mL) = 1.2 M`
c. `[Ba^(2+)] = (100 "mmol")/(100 mL)`
mmoles of `overset(ɵ)(O)H` left `= 200 - 120 = 80 "mmol"`