The law of multiple proportions is not illustrated by which pair of compounds

Options

A. CO and `CO_(2)`
B. CuO and `Cu_(2)O`
C. `CO_(2) ` and `H_(2) CO_(3)`
D. `SO_(2)` and `SO_(3)`

Answer

To solve the question regarding which pair of compounds does not illustrate the law of multiple proportions, we will follow these steps:

### Step 1: Understand the Law of Multiple Proportions
The law of multiple proportions 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 a ratio of small whole numbers.

### Step 2: Analyze the Given Options
We need to analyze the given pairs of compounds to see if they follow the law of multiple proportions.

1. **CO and CO2**:
- In carbon monoxide (CO), the ratio of carbon to oxygen is 1:1.
- In carbon dioxide (CO2), the ratio of carbon to oxygen is 1:2.
- Since these ratios (1:1 and 1:2) are in a simple whole number ratio, this pair illustrates the law of multiple proportions.

2. **SO2 and SO3**:
- In sulfur dioxide (SO2), the ratio of sulfur to oxygen is 1:2.
- In sulfur trioxide (SO3), the ratio of sulfur to oxygen is 1:3.
- The ratios (1:2 and 1:3) are also in a simple whole number ratio, thus this pair illustrates the law of multiple proportions.

3. **CO2 and H2CO3**:
- In carbon dioxide (CO2), the ratio of carbon to oxygen is 1:2.
- In carbonic acid (H2CO3), the ratio of carbon to oxygen is 1:3 (considering the total number of oxygen atoms).
- However, since H2CO3 contains hydrogen and the ratios of the elements are not strictly in a simple whole number ratio when compared to CO2, this pair does not illustrate the law of multiple proportions.

### Step 3: Conclusion
Based on the analysis, the pair of compounds that does not illustrate the law of multiple proportions is **CO2 and H2CO3**.

### Final Answer
The law of multiple proportions is not illustrated by the pair of compounds **CO2 and H2CO3**.

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