Amongst the following options which do follow law of multiple proportion ?

Options

A. Calcium Carbonate and Barium Carbonate
B. Sodium chloride and potassium chloride
C. Sulphur dioxide and sulphur trioxide
D. Carbon dioxide and sulphur dioxide

Explanation

To determine which compounds follow the law of multiple proportions, we first need to understand what this law states. The law of multiple proportions, proposed by John Dalton, 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 can be expressed in a ratio of small whole numbers.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given are:
- Calcium carbonate (CaCO₃)
- Barium carbonate (BaCO₃)
- Sodium chloride (NaCl)
- Potassium chloride (KCl)
- Sulfur dioxide (SO₂)
- Sulfur trioxide (SO₃)
- Carbon dioxide (CO₂)
- Sulfur (S)

2. **Analyze Each Pair**:
- **Calcium Carbonate and Barium Carbonate**:
- These compounds contain different metal ions (Ca and Ba) but share the same carbonate ion (CO₃). Since the elements involved are different, they do not follow the law of multiple proportions.

- **Sodium Chloride and Potassium Chloride**:
- Similar to the previous pair, these compounds contain different metal ions (Na and K) but share the same chloride ion (Cl). Thus, they do not follow the law of multiple proportions.

- **Sulfur Dioxide and Sulfur Trioxide**:
- Both compounds contain the same element (sulfur) and differ only in the number of oxygen atoms.
- For SO₂: 1 sulfur atom combines with 2 oxygen atoms.
- For SO₃: 1 sulfur atom combines with 3 oxygen atoms.
- The ratio of the masses of oxygen in these compounds can be calculated:
- Mass of O in SO₂ = 2 × 16 g = 32 g
- Mass of O in SO₃ = 3 × 16 g = 48 g
- The ratio of the masses of oxygen = 32 g : 48 g = 2 : 3, which is a whole number ratio. Thus, they follow the law of multiple proportions.

- **Carbon Dioxide and Sulfur Dioxide**:
- These compounds contain different elements (C in CO₂ and S in SO₂). Therefore, they do not follow the law of multiple proportions.

3. **Conclusion**:
- The only pair that follows the law of multiple proportions is **Sulfur Dioxide (SO₂) and Sulfur Trioxide (SO₃)**.

### Final Answer:
**Sulfur Dioxide (SO₂) and Sulfur Trioxide (SO₃) follow the law of multiple proportions.**