Question

Elements A and B form two different compounds. In first case 0.52 grams of A combines with 0.72 grams of B and in second case 0.15 grams of A combines with 0.65 grams of B. Show that these data illustrate the Law of multiple proportion.

Answer 1

Law of multiple proportions:

Dalton stated that “when two elements mix for the formation of two compounds or more compounds then the ratio of mass of one element that combines with a “fixed mass” of the other element in the two compounds is a simple whole number ratio”.

From the given data,

In a compound I, 0.52 g of A combines with 0.72 g of B.

Thus, one gram of A combines with $\frac { 0.72 }{ 0.52 } g$ of B

1.4 g of B combines 1 g of A

In compound II, 0.15 g of A combines with 0.65 g of B

Thus, 1 g of A combines with $\frac { 0.65 }{ 0.15 } g$ of B

4.3 g of B combines with 1 g of A

Therefore,  

$\begin{matrix} 4.3\quad g\quad of\quad B \\ 3 \end{matrix}\quad :\quad \begin{matrix} 1.4g\quad of\quad B \\ 1 \end{matrix}$

Thus, the mass of B which combines with 1 g of A in two different compounds have a simple ratio.