Which amongst the following is not a base?

Options

A. NaOH
B. KOH
C. `NH_(4)OH`
D. `C_(2)H_(5)OH`

Explanation

To determine which amongst the given options is not a base, we need to understand the definition of a base according to the Arrhenius theory. A base is a substance that furnishes hydroxide ions (OH⁻) when dissolved in water.

### Step-by-Step Solution:

1. **Understand the Definition of a Base**:
According to the Arrhenius theory, a base is defined as a substance that produces hydroxide ions (OH⁻) in an aqueous solution.

2. **Identify Common Bases**:
Examples of common bases include sodium hydroxide (NaOH), potassium hydroxide (KOH), and ammonium hydroxide (NH₄OH). When these substances are dissolved in water, they dissociate to release OH⁻ ions.

3. **Analyze the Given Compounds**:
Let's examine the compounds provided in the options. We need to identify which one does not produce OH⁻ ions when dissolved in water.

4. **Examine C2H5OH (Ethyl Alcohol)**:
One of the compounds is C₂H₅OH, which is ethyl alcohol. Although it contains an OH group, it does not produce hydroxide ions in the same way that bases do. Instead, it behaves more like an acid in some reactions and is classified as an alcohol.

5. **Conclusion**:
Since ethyl alcohol (C₂H₅OH) does not furnish OH⁻ ions in solution, it is not considered a base. Therefore, the correct answer is that C₂H₅OH is not a base.

### Final Answer:
C₂H₅OH (Ethyl Alcohol) is not a base.

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