Which of the following catalysts is used to convert an alkyne $(-C \equiv C-)$ to form a $cis$-alkene?

Alkene $X$ $\xrightarrow[\Delta]{KMnO_4}$ (Butan$-2-$one) $+$ (Pentanoic acid). $X$ is

In the reaction $CH_3CH_2CH_2Br$ $\xrightarrow{aq. NaOH} (X)$ $\xrightarrow{Al_2O_3, \text{Heat}} (Y)$ $\xrightarrow{HOCl} (Z)$,what is $Z$?

The number of alkenyl groups possible from $C_{4}H_{7}$ are

For the following reactions,the major products are shown: $H_2C=CH-CH=CH_2$ $\xrightarrow[0^\circ C]{HBr} CH_2=CH-CH(Br)-CH_3$ $\xrightarrow{25^\circ C} Br-CH_2-CH=CH-CH_3$. These provide an example of $1$ control at low temperature and $2$ control at higher temperature.

The ozonolysis products of an olefin are $CHO-CHO$ and $CHO-CH_2-CH_2-CHO$. The olefin is: