Which of the following is the relative molecular mass of a compound which has empirical formula CH2O? (H = 1; C = 12; O = 16)

A. 42
B. 45
C. 126
D. 180
E. 145

Correct Answer:

Option D – 180

Explanation

Empirical formula = CH2O

= 12 + (2 x 1) + 16

= 30

Molecular formula = (CH2O)n, where n is a whole number.

= 30n

∴ From the options, only 180 is a multiple of 30. Hence, that is the only likely molecular mass with respect to CH2O.