Isomers of Alkenes
Isomers are compounds that have the same molecular formula but differ in their structural arrangement or spatial orientation. Alkenes are hydrocarbons that contain a carbon-carbon double bond. In this question, we need to determine the number of isomers of alkenes that, upon catalytic hydrogenation, produce 2,2,3,5 - tetramethyl hexane.

Analysis
To solve this problem, we need to consider the conditions of the catalytic hydrogenation process. Hydrogenation of alkenes involves the addition of hydrogen (H2) across the double bond, resulting in the formation of a saturated compound, an alkane. In this case, the product of the hydrogenation reaction is specified as 2,2,3,5 - tetramethyl hexane.

Key Information
- The molecular formula of 2,2,3,5 - tetramethyl hexane is C10H22.
- The hydrogenation of an alkene adds 2 hydrogen atoms across the double bond.

Explanation
To determine the number of isomers that produce 2,2,3,5 - tetramethyl hexane upon hydrogenation, we need to consider the possible structural arrangements of the alkene.

1. Start with the Molecular Formula
The molecular formula of 2,2,3,5 - tetramethyl hexane is C10H22. This means that the alkene must have 10 carbon atoms and 22 hydrogen atoms.

2. Determine the Number of Carbons in the Alkene
Since the product is a hexane, it must have 6 carbon atoms. This leaves us with 4 remaining carbon atoms to distribute among the methyl groups.

3. Consider the Structural Arrangements
To generate different isomers, we need to consider the position of the double bond and the arrangement of the methyl groups.

4. Possible Isomers
Based on the given molecular formula and the conditions of the hydrogenation reaction, we can identify the following isomers:
- 2,2,3,5 - tetramethyl hexene
- 2,3,3,4 - tetramethyl hexene
- 2,2,3,4 - tetramethyl hexene
- 3,3,4,5 - tetramethyl hexene
- 2,3,3,5 - tetramethyl hexene
- 2,3,4,5 - tetramethyl hexene
- 2,2,4,5 - tetramethyl hexene

5. Explanation of Isomers
Each of these isomers has a different arrangement of the methyl groups and the position of the double bond. When these isomers undergo catalytic hydrogenation, 2 hydrogen atoms are added across the double bond, resulting in the formation of 2,2,3,5 - tetramethyl hexane.

Conclusion
In total, there are 7 different isomers of alkenes that, upon catalytic hydrogenation, produce 2,2,3,5 - tetramethyl hexane. Each isomer has a unique arrangement of methyl groups and a different position of the double bond.