When an alcohol is heated with excess of conc. `H_2 SO_4` at about `170^@`C, it gets dehydrated to form alkene(s). In this reaction, conc. `H_2 SO_4` acts as a dehydrating agent.
If boiling point of an alkene formed in a dehydration reaction of an alcohol is `-6^@ `C then, which of the following could be the boiling points of succeeding and preceding members of this alkene in its homologous series respectively

Options

A. `-48^@ C and - 104^@ C`
B. `30^@ C and 64^@ C `
C. `-104^@ C and -48^@ C `
D. `30^@ and -48^@`

Answer

To solve the problem, we need to determine the boiling points of the succeeding and preceding members of the alkene formed during the dehydration of an alcohol. Given that the boiling point of the alkene formed is -6°C, we will identify the alkene and then find the boiling points of its neighboring members in the homologous series.

### Step-by-Step Solution:

1. **Identify the Alkene**:
The problem states that the boiling point of the alkene formed from the dehydration of an alcohol is -6°C. The alkene with a boiling point of -6°C is 1-butene (C4H8).

**Hint**: Look for alkenes in the homologous series and check their boiling points.

2. **Determine the Preceding Member**:
The preceding member of 1-butene in the homologous series is propene (C3H6). The boiling point of propene is approximately -48°C.

**Hint**: The preceding member can be found by reducing the carbon count by one in the alkene formula.

3. **Determine the Succeeding Member**:
The succeeding member of 1-butene is 1-pentene (C5H10). The boiling point of 1-pentene is approximately 30°C.

**Hint**: The succeeding member can be found by increasing the carbon count by one in the alkene formula.

4. **Final Answer**:
Thus, the boiling points of the preceding and succeeding members of the alkene (1-butene) are:
- Preceding member (propene): -48°C
- Succeeding member (1-pentene): 30°C

### Conclusion:
The boiling points of the succeeding and preceding members of the alkene in its homologous series are 30°C and -48°C, respectively.