Complete the following:
In a ______ acid, the number of the replaceable H atoms in its molecule is two.

Explanation

To complete the statement: "In a ______ acid, the number of the replaceable H atoms in its molecule is two," we need to identify the type of acid that has two replaceable hydrogen atoms.

### Step-by-Step Solution:

1. **Understand the Concept of Basicity**: Basicity refers to the number of hydrogen ions (H⁺) that an acid can donate when dissolved in water. This is directly related to the number of replaceable hydrogen atoms in the acid's molecule.

2. **Identify Types of Acids Based on Basicity**:
- **Monobasic Acid**: An acid with one replaceable hydrogen atom (e.g., HCl, HNO₃).
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