What volume of 0.20 mol dm -³ NaOH solution would yield 5.0 g of NaOH on evaporation to dryness? [NaOH = 40g mol-1]

A. 400 cm³
B. 625 cm³
C. 1000 cm³
D. 1600 cm³

Correct Answer: Option B

B. 625 cm³

Explanation
Conc. g/dm³ = 0.20 x 40 gmol -1 = 8 g/dm³

1000 cm³ of 0.20m NaOH contains 8g of NaOH

:. 5g of NaOH will be contained in (5/8 x 1000) = 625cm³