Which one of the following is the salt of a binary acid?

Options

A. calcium sulphate
B. magnesium bromide
C. zinc phosphate
D. sodium carbonate

Explanation

To determine which of the given options is a salt of a binary acid, we need to understand what a binary acid is and then analyze each option provided.

### Step-by-Step Solution:

1. **Understand Binary Acids**:
- A binary acid is an acid that consists of only two different elements, typically hydrogen and a non-metal. Common examples include hydrochloric acid (HCl) and hydrobromic acid (HBr).

2. **Analyze Each Option**:
- **Calcium Sulfate (CaSO4)**:
- This compound is derived from sulfuric acid (H2SO4), which contains three elements (H, S, O). Therefore, it is not a salt of a binary acid.

- **Magnesium Bromide (MgBr2)**:
- This compound is derived from hydrobromic acid (HBr), which is a binary acid (it contains only H and Br). Therefore, magnesium bromide is a salt of a binary acid.

- **Zinc Phosphate (Zn3(PO4)2)**:
- This compound is derived from phosphoric acid (H3PO4), which contains more than two different elements (H, P, O). Therefore, it is not a salt of a binary acid.

- **Sodium Carbonate (Na2CO3)**:
- This compound is derived from carbonic acid (H2CO3), which also contains more than two different elements (H, C, O). Therefore, it is not a salt of a binary acid.

3. **Conclusion**:
- The only compound that is a salt of a binary acid is **Magnesium Bromide (MgBr2)**.

### Final Answer:
**Magnesium Bromide (MgBr2) is the salt of a binary acid.**

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