The correct option is 2 only
Explanation
The Law of Definite Proportions, also known as the Law of Constant Composition, was proposed by Joseph Proust. It governs the stoichiometric composition of chemical compounds, stating that elements combine in fixed ratios by mass to form specific compounds.
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Statement 1 is Incorrect:
The law explicitly states that a pure chemical compound always consists of the same elements combined together in the same fixed proportion by weight (mass). For example, pure water ($H_2O$) always contains hydrogen and oxygen in the ratio of 1:8 by mass, regardless of the sample size.
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Statement 2 is Correct:
A fundamental implication of this law is that the composition of a compound is independent of the source from which it is obtained or the method used for its preparation. Whether water is obtained from a river, a well, or synthesized in a laboratory, the ratio of hydrogen to oxygen by mass remains constant.
Key Takeaway:
The Law of Definite Proportions establishes that the chemical composition of a pure compound is invariant and does not change based on its origin or method of synthesis.