Which of the following is the strongest acid in water?

Options

A. `HNO_(3)`
B. `H_(2)SO_(4)`
C. HCI
D. `C_(2)H_(5) OH`

Answer

To determine which of the following is the strongest acid in water among the given options (HNO3, H2SO4, HCl, and C2H5OH), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Nature of the Acids**:
- We need to classify the given acids based on their strength in aqueous solution.
- The options are:
- HNO3 (Nitric Acid)
- H2SO4 (Sulfuric Acid)
- HCl (Hydrochloric Acid)
- C2H5OH (Ethanol)

2. **Understand Strong and Weak Acids**:
- Strong acids are those that completely dissociate in water to produce H⁺ ions.
- Weak acids do not fully dissociate and therefore produce fewer H⁺ ions in solution.

3. **Analyze Each Acid**:
- **HNO3**: This is a strong acid and dissociates completely in water.
- **H2SO4**: This is also a strong acid and dissociates completely in its first dissociation step. The second dissociation is also significant, making it a very strong acid.
- **HCl**: This is another strong acid that completely dissociates in water.
- **C2H5OH**: Ethanol is a weak acid and does not dissociate significantly in water.

4. **Compare the Strengths**:
- Since HNO3, H2SO4, and HCl are all strong acids, they will produce a high concentration of H⁺ ions in solution.
- However, H2SO4 is considered one of the strongest acids due to its ability to produce more H⁺ ions compared to HNO3 and HCl.

5. **Conclusion**:
- Among the options, H2SO4 is the strongest acid in water, followed by HNO3 and HCl. C2H5OH is a weak acid and does not contribute significantly to acidity.

### Final Answer:
**The strongest acid in water among the given options is H2SO4.**