Question

Compound X has the formula C8H14. X reacts with one molar equivalent of hydrogen in the presence of a palladium catalyst to form a mixture of cis- and trans-1-ethyl-3-methylcyclopentane. Treatment of X with ozone followed by zinc in aqueous acid gives a ketone and formaldehyde (CH2=O). What is the structure of X?

Answer 1

Answer:

1-Ethyl-3-methylidenecyclopentane  

Step-by-step explanation:

Formula = C₈H₁₄. An alkane has formula C₈H₁₈. ∴ X contains 2 double bonds, 2 rings, or 1 ring and 1 double bond.

X absorbs only 1 mol of hydrogen. ∴ X contains 1 ring and 1 double bond.

Hydrogenation gives 1-ethyl-3-methylcyclopentane.

Ozonolysis gives formaldehyde, so X must contain a =CH₂ group.  

Hydrogenation of X converted the =CH₂ to -CH₃.

X is 1-ethyl-3-methylidenecyclopentane.

You can see the reactions in the image below.