Amongest the following the maximum number of alkenes which shows geometrical isomers are 1-pentene, 2-butene, 2-pentene, 1-butene ,propne, 2,3-dimethyl-2-butene, 3-hexene, 1-hexene

Explanation

To determine which of the given alkenes can exhibit geometrical isomerism, we need to analyze each compound based on its structure and the presence of a double bond. Geometrical isomerism occurs in alkenes when there are different groups attached to the carbon atoms involved in the double bond.

### Step-by-Step Solution:

1. **Identify the Alkenes:**
The alkenes given in the question are:
- 1-pentene
- 2-butene
- 2-pentene
- 1-butene
- Propene
- 2,3-dimethyl-2-butene
- 3-hexene
- 1-hexene

2. **Draw the Structures:**
- **1-pentene (C5H10)**: CH2=CH-CH2-CH2-CH3
- **2-butene (C4H8)**: CH3-CH=CH-CH3 (can be cis or trans)
- **2-pentene (C5H10)**: CH3-CH=CH-CH2-CH3 (can be cis or trans)
- **1-butene (C4H8)**: CH2=CH-CH2-CH3
- **Propene (C3H6)**: CH2=CH-CH3
- **2,3-dimethyl-2-butene (C6H12)**: (CH3)2C=CH-CH3 (can be cis or trans)
- **3-hexene (C6H12)**: CH3-CH2-CH=CH-CH2-CH3 (can be cis or trans)
- **1-hexene (C6H12)**: CH2=CH-CH2-CH2-CH2-CH3

3. **Analyze for Geometrical Isomerism:**
- **1-pentene**: No geometrical isomers (both carbons in the double bond have identical groups).
- **2-butene**: Yes, can have cis and trans isomers.
- **2-pentene**: Yes, can have cis and trans isomers.
- **1-butene**: No geometrical isomers (both carbons in the double bond have identical groups).
- **Propene**: No geometrical isomers (both carbons in the double bond have identical groups).
- **2,3-dimethyl-2-butene**: Yes, can have cis and trans isomers.
- **3-hexene**: Yes, can have cis and trans isomers.
- **1-hexene**: No geometrical isomers (both carbons in the double bond have identical groups).

4. **Count the Alkenes with Geometrical Isomers:**
The alkenes that can exhibit geometrical isomerism are:
- 2-butene
- 2-pentene
- 2,3-dimethyl-2-butene
- 3-hexene

Thus, there are **4 alkenes** that can show geometrical isomers.

### Final Answer:
The maximum number of alkenes that show geometrical isomers among the given options is **4**.