Propene is not the product obtained by dehydration of :

Options

A. 2-Propanol
B. 1-propanol
C. Propanal
D. n-propyl alcohol

Answer

To solve the question, "Propene is not the product obtained by dehydration of:", we need to analyze each option provided and determine whether propene is formed through dehydration of the given alcohols.

### Step-by-Step Solution:

1. **Understand Dehydration of Alcohols**: Dehydration of alcohols typically involves the removal of water (H2O) to form alkenes. This reaction usually requires an acid catalyst, such as concentrated sulfuric acid or phosphoric acid.

2. **Analyze Each Option**:
- **Option 1: 2-Propanol**:
- When 2-propanol (isopropyl alcohol) undergoes dehydration, it forms propene (C3H6) as follows:
\[ \text{2-Propanol} \xrightarrow{\text{H}_2\text{SO}_4} \text{Propene} + \text{H}_2\text{O} \]
- **Product**: Propene is formed.

- **Option 2: 1-Propanol**:
- 1-Propanol (also known as n-propyl alcohol) also undergoes dehydration to yield propene:
\[ \text{1-Propanol} \xrightarrow{\text{H}_2\text{SO}_4} \text{Propene} + \text{H}_2\text{O} \]
- **Product**: Propene is formed.

- **Option 3: Propanal**:
- Propanal is an aldehyde, not an alcohol. Aldehydes do not undergo dehydration like alcohols do. Instead, they can undergo different reactions, but dehydration to form an alkene is not one of them.
- **Product**: No propene is formed.

- **Option 4: n-Propyl Alcohol**:
- n-Propyl alcohol is the same as 1-propanol. Therefore, it will also lead to the formation of propene upon dehydration:
\[ \text{n-Propyl Alcohol} \xrightarrow{\text{H}_2\text{SO}_4} \text{Propene} + \text{H}_2\text{O} \]
- **Product**: Propene is formed.

3. **Conclusion**: The only compound from which propene is not obtained upon dehydration is **Option 3: Propanal**.

### Final Answer:
**Propene is not the product obtained by dehydration of: Option 3 - Propanal.**