Names of which of the following end in `-ous` acid ?

Options

A. `HNO_(2)`
B. `H_(2)CO_(3)`
C. `H_(2)SO_(3)`
D. `HPO_(3)`

Explanation

To determine which of the following acids have names that end in "-ous," we will analyze each given compound step by step.

### Step-by-Step Solution:

1. **Identify the first compound: HNO2**
- The name of HNO2 is **nitrous acid**.
- Since "nitrous" ends with "-ous," this is a correct option.

2. **Identify the second compound: H2CO3**
- The name of H2CO3 is **carbonic acid**.
- "Carbonic" does not end with "-ous," so this is not a correct option.

3. **Identify the third compound: H2SO3**
- The name of H2SO3 is **sulphurous acid**.
- Since "sulphurous" ends with "-ous," this is a correct option.

4. **Identify the fourth compound: H2SO4**
- The name of H2SO4 is **sulfuric acid**.
- "Sulfuric" does not end with "-ous," so this is not a correct option.

5. **Identify the fifth compound: H3PO3**
- The name of H3PO3 is **meta phosphoric acid**.
- "Meta phosphoric" does not end with "-ous," so this is not a correct option.

### Conclusion:
The acids whose names end in "-ous" are:
- HNO2 (Nitrous acid)
- H2SO3 (Sulphurous acid)

Thus, the correct options are **1 and 3**.

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