Which of the given molecules obey the law of definite proportion

 

Solution:

Concept: The law of definite proportions is coined by Louis Proust.

The law of definite proportions also contributed to the development of Dalton’s atomic theory.

Water molecule involves the combinations of hydrogen and oxygen atoms in a 2:1 ratio. Since they occur in a fixed ratio of mass, water molecules obey the law of definite proportions.

Hence water obeys the law of definite proportion.