$Propanal$ and $pentan-3-one$ are ozonolysis products of:

The product of the following reaction is:

$17 \, mg$ of a hydrocarbon ($M$.$F$. $C_{10}H_{16}$) takes up $8.40 \, mL$ of $H_2$ gas measured at $0^{\circ}C$ and $760 \, mm$ of $Hg$. Ozonolysis of the same hydrocarbon yields acetone,formaldehyde,and a compound with the structure $CH_3-CO-CH_2-CH_2-CHO$. The number of double bonds present in the hydrocarbon is $...........$.

Which of the following alkenes does not undergo anti-Markovnikov addition of $HBr$?

Assertion : $trans-2-Butene$ on reaction with $Br_2$ gives $meso-2,3-dibromobutane$.
Reason : The reaction involves $syn-addition$ of bromine.

The major product formed during the reaction of $1$-methylcyclopentene with $CH_3CO_3H$ is