Which alkene reacts fastest with $H_2$ under catalytic hydrogenation conditions?

Compound $(C)$ in the above sequence of reaction is:

What is the product $(Q)$ of the following reaction?

Identify the reaction that does not produce an alkene.

The cycloalkane $(X)$ on bromination consumes one mole of bromine per mole of $(X)$ and gives product $(Y)$ in which $C:Br$ ratio is $3:1$. The percentage of bromine in the product $(Y)$ is $ . . . . . . \%$ (Nearest integer).
(Given: Molar mass in $g \ mol^{-1}$, $H:1, C:12, O:16, Br:80$)

Which of the following compounds gives a positive Baeyer's test but does not form a white precipitate with ammoniacal silver nitrate solution?