Answer:
See explanation and image attached
Explanation:
If we look at the question closely, we will discover that two molar equivalents of hydrogen gas was used to obtain cyclooctane rom X. This implies that the compound X is an alkyne and it must be cyclooctyne since the hydrogen serves to reduce the triple bond and yield the corresponding alkane.
This is confirmed by the second statement which is ozonolysis of the X with zinc in aqueous acid which gave two molar equivalents of the same dialdehyde.
Image credit: Chem spider