On evaporation to dryness, 250 cm3 of saturated solution of salt X with relative molar mass 101 gave 50.5g of the. What is the soluility of the salt?

A.

1.0 mol dm-3

B.

2.0 mol dm-3

C.

4.0 moldm-3

D.

5.0 moldm-3

Correct answer is B

50.5g 0f salt X is contained in 250cm3,

what mass of X is contained in 1000cm3 

= (50.5 x 1000) ÷ 250 = 202g

no of moles of salt x = mass÷ molar mass

= 202÷ 101 = 2.0mol/dm3