Answer:

Given:
- Molecular formula of alkyne X: C10H18
- Hydrogenation of X gives an alkane C10H22
- The alkane contains two -CH2 groups and six -CH3 groups

Steps to determine the IUPAC name of X:

1. Determine the structure of the alkane:
- The alkane C10H22 contains two -CH2 groups and six -CH3 groups.
- Since each -CH2 group contributes 2 hydrogen atoms and each -CH3 group contributes 3 hydrogen atoms, we can calculate the total number of hydrogen atoms in the alkane:
- (2 * 2) + (6 * 3) = 4 + 18 = 22
- This confirms that the alkane C10H22 has the correct number of hydrogen atoms.

2. Determine the structure of the alkyne:
- Since the hydrogenation of X leads to the formation of an alkane with two -CH2 groups and six -CH3 groups, we can deduce that the alkyne X initially had two triple bonds (C≡C) and no branches.
- The hydrogenation of the triple bonds in X would result in the addition of two hydrogen atoms for each triple bond, leading to the formation of two -CH2 groups.

3. Determine the molecular formula of the alkyne:
- The molecular formula of the alkane C10H22 contains the maximum number of hydrogen atoms for its carbon skeleton.
- Since each -CH2 group contributes 2 hydrogen atoms and each -CH3 group contributes 3 hydrogen atoms, we can calculate the total number of hydrogen atoms in the alkyne:
- (2 * 2) + (6 * 3) = 4 + 18 = 22
- This confirms that the molecular formula of the alkyne X is C10H18.

4. Determine the IUPAC name of the alkyne:
- The alkyne X has a molecular formula of C10H18.
- To determine the IUPAC name, we need to determine the longest carbon chain in the molecule and identify the functional groups present.
- Since the alkyne has 10 carbon atoms, the longest carbon chain is a decane.
- The functional group present in the alkyne is a triple bond (C≡C).
- Based on this information, the IUPAC name of X is 2-Decyne.

Conclusion:
The IUPAC name of the alkyne X with the molecular formula C10H18 is 2-Decyne.