Law of multiple proportions is illustrated by one of the following pairs.

Options

A. `H_(2)S and SO_(2)`
B. `NH_(3) and NO_(2)`
C. `Na_(2)S and Na_(2)O`
D. `N_(2)O and NO`

Explanation

To solve the question regarding the Law of Multiple Proportions, we need to follow these steps:

### Step-by-Step Solution:

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

2. **Identify the Compounds**:
We need to analyze the pairs of compounds given in the options to see if they illustrate this law.

3. **Examine Each Option**:
- **Option 1: H2S and SO2**:
- Here, we have sulfur (S) and hydrogen (H) combined in different compounds. Since the elements are different, this option does not illustrate the law.
- **Option 2: H2O and H2O2**:
- This option contains hydrogen and oxygen, but they are not different compounds of the same elements, so this option is also incorrect.
- **Option 3: CH4 and C2H6**:
- Here, we have carbon (C) and hydrogen (H) in different compounds, but again, they do not illustrate the law as they do not have a fixed mass of one element combining with a varying mass of another.
- **Option 4: N2O and NO**:
- This option contains nitrogen (N) and oxygen (O). Here, we can analyze the mass of oxygen which remains constant (16 g) while the mass of nitrogen varies (14 g in NO and 28 g in N2O). The ratio of the masses of nitrogen combining with a fixed mass of oxygen is 1:2, which is a simple whole number ratio.

4. **Conclusion**:
Based on the analysis, the correct option that illustrates the Law of Multiple Proportions is **Option 4: N2O and NO**.