Question

State and explain law of multiple proportions with the help of an example.

Answer 1

Law of multiple proportions:

• When two elements combine to generate more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of tiny whole numbers, according to the law of multiple proportions.
• The English scientist John Dalton established the rule in $1803$; its validation over a wide range of compounds is regarded as the most strong evidence in support of Dalton's idea that matter is made up of indivisible atoms.

Example:

• Let us assume two molecules $\mathrm{CO}$(carbon monoxide) and ${\mathrm{CO}}_2$(carbon dioxide).
• $\mathrm{CO}=12\mathrm{grams}\mathrm{of}\mathrm{carbon}+16\mathrm{grams}\mathrm{of}\mathrm{Oxygen}.$
• ${\mathrm{CO}}_2=12\mathrm{grams}\mathrm{carbon}+32\mathrm{grams}\mathrm{of}\mathrm{Oxygen}.$
• The ratio of the mass of oxygen in the given two compounds is $16:32=1:2$
• Thus, the law of multiple proportions is proved.