The law of multiple proportion was discovered by

Options

A. John Dalton
B. Richter
C. Joseph Proust
D. A. Lavoisier

Explanation

**Step-by-Step Solution:**

1. **Understanding the Law of Multiple Proportions**: The law states that when two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in the ratio of small whole numbers.

2. **Example of the Law**: Consider carbon and oxygen. Carbon can combine with oxygen to form carbon monoxide (CO) and carbon dioxide (CO2). In these compounds, the mass of carbon remains constant while the mass of oxygen varies.

3. **Calculating the Ratios**:
- For CO: The mass of carbon is 12 g and the mass of oxygen is 16 g.
- For CO2: The mass of carbon is still 12 g, but the mass of oxygen is now 32 g (since CO2 has two oxygen atoms).
- The ratio of the mass of oxygen in CO to the mass of oxygen in CO2 is 16:32, which simplifies to 1:2.

4. **Conclusion**: The law of multiple proportions was proposed by John Dalton, who was a pioneer in atomic theory.

5. **Final Answer**: Therefore, the law of multiple proportions was discovered by John Dalton.

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