Question

What are the limitations of law of definite proportions?

• A. The law is not true if different isotopes of elements are involved in making a chemical compound.
• B. The law is not true if elements combine in same ratio but produce different compounds.
• C. Both A and B.
• D. None of above.

Answer 1

The correct option is C Both A and B.

The law fails to be applied in the case of isotopic elements. This is also not applicable when there are possibilities of making two or more compounds from the same elements. In this case, we can take the example of alcohol and dimethyl ether.

As both the compounds have the same chemical formula $C_2{H}_{6}O$ and the elements carbon, hydrogen, and oxygen are present in the same ratio, that is, 12:3:8 in mass. But the same ratio is given in two different compounds, which are ethyl alcohol and dimethyl ether.

Hence, the correct option is $C$.