Question

example of law of constant proposition

Answer 1

formation of water
2 moles of hydrogen nd 1 mole of oxygen

Answer 2

Law of constant or definite proportions:
given by Joseph Proust in 1799.
"it states that a chemical compound always contains exactly the same proportion of elements by mass."
example:- pure water obtained from river,sea,well etc contains hydrogen and oxygen combined together in the ratio of 1:8 by mass.
hope it helps you: )