Question

Explain law of multiple proportions.

Answer 1

Hint:
Multiple proportions law is a rule of stoichiometry. This law of multiple proportions is also known as Dalton’s law, because this law was announced (1803) by the English chemist John Dalton.

Complete step by step answer:
> The law of multiple proportions, states that when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.
> For understanding let’s take some examples like: $CO$, \[C{{O}_{2}}\] , oxides of $N$ ,\[S{{O}_{2}}\] etc. and below given is their explanations.
Example: there are five different oxides of nitrogen (N) and the weights of oxygen (O) in combination with 14 grams of nitrogen are, in increasing order: 8, 16, 24, 32, and 40 gms, or in a ratio of 1, 2, 3, 4, 5.
> We know that compounds are made of different elements. But this law is applicable for compounds which are made up of the same elements, like carbon monoxide (CO) and carbon dioxide (\[C{{O}_{2}}\]). Both compounds are made of carbon (C) atoms and oxygen (O) atoms. But the ratios of carbon(C) and oxygen (O) in each compound is different.
> The law of multiple proportions, states that when two elements combine to form more than one compound, the mass of one element, which combines with a fixed mass of the other element, will always be ratios of whole numbers.
> If we take \[S{{O}_{2}}\] and \[C{{O}_{2}}\], one compound has sulfur (S) and one has carbon (C), so, here the law of multiple proportions is not valid.

Note:
The law of multiple proportions is an extension of the law of definite composition, which states that compounds will consist of defined ratios of elements. You should remember that the law of multiple proportions only applies to compounds composed of the same elements.