Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weight of carbon and oxygen is respectively `12:16` and `12:32`. These figures illustrate the :
(a)law of multiple proportions
(b)law of reciprocal proportions
(c)law of conservation of mass
(d)law of constant proportions

Options

A. law of multiple proportions
B. law of reciprocal proportions
C. law of conservation of mass
D. law of constant proportains

Answer

To solve the question, we need to analyze the information provided about the formation of carbon monoxide (CO) and carbon dioxide (CO₂) from carbon and oxygen. We will determine which law of stoichiometry is illustrated by the given mass ratios.

### Step-by-Step Solution:

1. **Identify the Compounds and Their Ratios**:
- Carbon monoxide (CO) has a mass ratio of carbon to oxygen as 12:16.
- Carbon dioxide (CO₂) has a mass ratio of carbon to oxygen as 12:32.

2. **Calculate the Mass of Oxygen in Each Compound**:
- In CO: The mass of carbon is 12 g, and the mass of oxygen is 16 g.
- In CO₂: The mass of carbon is 12 g, and the mass of oxygen is 32 g.

3. **Compare the Mass of Oxygen**:
- For CO, the mass of oxygen is 16 g.
- For CO₂, the mass of oxygen is 32 g.
- The mass of carbon remains constant at 12 g in both compounds.

4. **Determine the Ratio of the Masses of Oxygen**:
- The ratio of the mass of oxygen in CO to that in CO₂ is 16:32.
- This simplifies to 1:2.

5. **Apply the Law of Multiple Proportions**:
- According to the law of multiple proportions, when two elements combine to form two or more compounds, the masses of one element that combine with a fixed mass of the other element can be expressed in a simple whole number ratio.
- Here, the fixed mass of carbon (12 g) combines with different masses of oxygen (16 g and 32 g), which gives us the ratio of 1:2.

6. **Conclusion**:
- Since the mass of carbon remains constant and the mass of oxygen changes in a simple ratio (1:2), this scenario illustrates the **law of multiple proportions**.

### Final Answer:
(a) Law of multiple proportions

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