14.8 g of salt (z)dissolved in 250 cm³ of distilled water gives a concentration of 0.80 mol dm-³. Calculate the molar mass of the salt (z).

A. 13.5 g mol-1
B. 18.5 g mol-1
C. 47.4 g mol-1
D. 74.0 g mol-1

Correct Answer: Option D

D. 74.0 g mol-1

Explanation

250cm³ of distilled water contains 14.8g of salt(z)
1cm³ of distilled water will contain 14.8×12/50 of salt (z)
:. 1000cm³ of distilled water will contain 14.8x1x1000/250 = 59.2g/dm³
0.80 = 59.2/molar mass
molar mass = 59.2  x 0.80

= 74.0 g/mol