Question

differentiate between
1.law of definite proportion
2. law of multiple proportion
3.law of reciprocal proportion

Answer 1

Law of Constant or definite Proportion :
In 1806, French chemist Joseph Proust stated that “Every pure substance always contains same elements combined in the same proportions by weight”
For ex., NaCl . Whatever be the method of preparation, NaCl contains 23 parts of Na and 35.5 parts of Cl.
Law of Multiple Proportions:
In 1803, English chemist John Dalton stated that “If two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.” For ex., In NH₃ and N₂H₄, the fixed mass of nitrogen requires hydrogen in the ratio of 3 : 2
Law of Reciprocal proportions:
In 1792 – 1794 Ritcher stated that, “when two different element separately combines with the fixed mass of third element, the proportion in which they combine with one another shall be either in the same ratio or some simple multiple of it.” For ex., CH₄ and CO₂, for the fixed mass of carbon hydrogen and oxygen combine to produce H₂O.