Who gave the statement of the law of definite proportions?

Law of definite proportions

• Law of Definite Proportion also called Proust's Law or Law of Constant Composition
• The Law of definite proportion is given by chemist Joseph Proust.
• The explanation for this law is provided by John Dalton.
• In this law, elements combine in simple ratios of natural numbers.
• "In a chemical substance, the elements are always present in definite proportions by mass”.

Example

• In ammonia, nitrogen and hydrogen are always present in the ratio $14:3$ by mass, whatever the method or the source from which it is obtained.