Which of the following compounds conform the law of multiple proportion?

Options

A. `HgCl_(2)`, and `Hg_(2)Cl_(2) `
B. `Na_(2)O` and CaO
C. NaCI and `BaCI_(2)`
D. `H_(3) PO_(4)` and `Ca_(3) (PO_(4))_(2)`

Answer

To determine which of the given compounds conforms to the law of multiple proportions, we need to analyze the ratios of the elements in each compound. The law of multiple proportions states that when two elements combine to form more than one compound, the ratios of the masses of one element that combine with a fixed mass of the other element can be expressed in simple whole numbers.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We are given the following compounds:
- HgCl2 (Mercury(II) chloride)
- Hg2Cl2 (Mercury(I) chloride)
- Na2O (Sodium oxide)
- CaO (Calcium oxide)
- NaCl (Sodium chloride)
- BaCl2 (Barium chloride)
- H3PO4 (Phosphoric acid)
- Ca3(PO4)2 (Calcium phosphate)

2. **Analyze the Ratios**:
- For **HgCl2** and **Hg2Cl2**:
- HgCl2 has 1 Hg and 2 Cl.
- Hg2Cl2 has 2 Hg and 2 Cl.
- The ratio of Hg in HgCl2 to Hg in Hg2Cl2 is 1:2, which is a simple whole number ratio.

- For **Na2O** and **CaO**:
- Na2O has 2 Na and 1 O.
- CaO has 1 Ca and 1 O.
- There is no simple whole number ratio between Na and Ca in these compounds.

- For **NaCl** and **BaCl2**:
- NaCl has 1 Na and 1 Cl.
- BaCl2 has 1 Ba and 2 Cl.
- Again, there is no simple whole number ratio between Na and Ba.

- For **H3PO4** and **Ca3(PO4)2**:
- H3PO4 has 3 H, 1 P, and 4 O.
- Ca3(PO4)2 has 3 Ca, 2 P, and 8 O.
- There is no simple whole number ratio between H and Ca.

3. **Conclusion**:
The only pair of compounds that conforms to the law of multiple proportions is **HgCl2** and **Hg2Cl2**.

### Final Answer:
The compounds that conform to the law of multiple proportions are **HgCl2 and Hg2Cl2**.

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