A hydrocarbon of formula C8H14 takes up one mole of H2 over Pd/C and, on ozonolysis followed by Zn/H2O, gives only a single product…

$\mathrm{C_8H_{14}}$ has two degrees of unsaturation; one $\mathrm{H_2}$ uptake means one $\mathrm{C{=}C}$ and one ring. Cleavage of a ring alkene gives a single acyclic dicarbonyl compound with all $8$ carbons. Octane-2,7-dione, $\mathrm{CH_3CO(CH_2)_4COCH_3}$, arises when the double bond carries one methyl on each carbon and the other four ring carbons are $\mathrm{CH_2}$ groups: 1,2-dimethylcyclohexene. 1-Methylcycloheptene would give a keto-aldehyde, and 1-ethylcyclohexene also gives a keto-aldehyde.