Which of the following statements indicates that law of multiple …

MCQ

Which of the following statements indicates that law of multiple proportion is being followed.

A
Sample of carbon dioxide taken from any source will always have carbon and oxygen in the ratio $1 : 2.$
✓
Carbon forms two oxides namely $\ce{CO_2}$ and $CO$, where masses of oxygen which combine with fixed mass of carbon are in the simple ratio $2 : 1.$
C
When magnesium burns in oxygen, the amount of magnesium taken for the reaction is equal to the amount of magnesium in magnesium oxide formed.
D
When magnesium burns in oxygen, the amount of magnesium taken for the reaction is equal to the amount of magnesium in magnesium oxide formed.

✓

Answer

Correct option: B.

Carbon forms two oxides namely $\ce{CO_2}$ and $CO$, where masses of oxygen which combine with fixed mass of carbon are in the simple ratio $2 : 1.$

The element, carbon, combines with oxygen to form two compounds, namely, carbon dioxide and carbon monoxide. In $CO_2, 12$ parts by mass of carbon combine with $32$ parts by mass of oxygen while in $CO, 12$ parts by mass of carbon combine with $16$ parts by mass of oxygen.
Therefore, the masses of oxygen combine with a fixed mass of carbon $(12$ parts$)$ in $\ce{CO_2}$ and $CO$ are $32$ and $16$ respectively. These masses of oxygen bear a simple ratio of $32 : 16$ or $2 : 1$ to each other.
This is an example of law of multiple proportions.