Question

Law of constant proportion states that:

In a chemical substance the elements are NOT present in a definite proportion by mass.

• A. True
• B. False

Answer 1

The correct option is B

False

Law of constant proportion or Law of definite proportions states that:

In a chemical substance, the elements are always present in a definite proportion by mass.

let's take an example of $H_{2}O$.

Here, the chemical substance is $H_{2}O$, elements are H and O and ratio will be 1:8 by mass.