Which of the following is not correctly matched:

Options

A. `H_(2)CrO_(4)` , Chromic acid
B. `HPO_(3)` , Metaphosphoric acid
C. `HNO_(4)` , Peroxynitric acid
D. `HClO_(3)` Chlorous acid

Explanation

To determine which of the given compounds is not correctly matched with its common name, we will analyze each option one by one.

### Step 1: Analyze Chromic Acid
- **Chemical Formula**: CrO3 (Chromic acid is often represented as H2CrO4)
- **Common Name**: Chromic Acid
- **Match Status**: Correctly matched.

### Step 2: Analyze Metaphosphoric Acid
- **Chemical Formula**: HPO3 (Metaphosphoric acid can be represented as H3PO3)
- **Common Name**: Metaphosphoric Acid
- **Match Status**: Correctly matched.

### Step 3: Analyze Peroxynitric Acid
- **Chemical Formula**: HNO4 (Peroxynitric acid is often represented as HNO3)
- **Common Name**: Peroxynitric Acid
- **Match Status**: Correctly matched.

### Step 4: Analyze Chloric Acid
- **Chemical Formula**: HClO2 (Chloric acid is represented as HClO3)
- **Common Name**: Chloric Acid
- **Match Status**: Incorrectly matched. The correct formula for chloric acid is HClO3, not HClO2.

### Conclusion
After analyzing all the options, we find that the last option regarding chloric acid is not correctly matched. Therefore, the answer is:

**Answer: D (Chloric Acid)**

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