A mixture of 200 mmol of `Ca(OH)_2 ` and 3g of sodium sulphate was dissolved in water and the volume was made up to 200 mL. The mass of calcium sulphate formed and the concentration of ` OH^(-)` in resulting solution, respectively, are: (Molar mass of `Ca(OH)_2 , Na_2SO_4 " and " CaSO_4` are 74, 143 and `136 g mol^(-1)` respectively, `K_(sp)` of `Ca (OH)_2` is ` 5 xx 10^(-6) ` )

Options

A. `13.6 g, 0.28 mol L^(-1)`
B. `1.9 g, 0.14 mol L^(-1)`
C. `1.9 g, 0.28 mol L^(-1)`
D. `13.6 g, 0.14 mol L^(-1)`

Answer

C

Explanation

`Ca(OH)_(2) + Na_(2)SO_(4) to CaSO_(4) + 2NaOH`
100 mmol 14 mmol
- - 14 mmol 28 mmol
Mass of `CaSO_(4) = 14xx10^(-3)xx136=1.9g`
`[OH^(-)]=28/100 = 0.28M`