Question

Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively $12:16$ and $12:32$.

These figures illustrate the:

• A. Law of multiple proportions
• B. Law of reciprocal proportions
• C. Law of conservation of mass
• D. Law of constant proportions

Answer 1

The correct option is A Law of multiple proportions

According to the law of multiple proportions, when two elements combine with each other to form two or more than two compounds, the masses of one of the elements which combine with a fixed mass of the other, bear a simple whole number ratio.

For example: In $CO:12$ parts by mass of carbon combine with $16$ part by mass of oxygen.

In $C{O}_2$, $12$ parts by mass of carbon combine with $32$ parts by mass of oxygen.

The ratio of masses of oxygen which combine with a fixed mass of carbon in these compounds is $16:32$ or $1:2$, which is a simple whole number ratio.