The octane number of diesel is increased by adding ..........

The major product $'A'$ of the following given reaction has $......\,sp^2$ hybridized carbon atoms.
$2,7-\text{Dimethyl}-2,6-\text{octadiene} \xrightarrow{H^{+}} A \text{ (Major Product)}$

What is the number of $\sigma$ and $\pi$ bonds in $Pent-1-en-4-yne$?

The product obtained by heating $(NH_4)_2SO_4$ and $KCNO$ is

For the following reaction scheme,percentage yields are given along the arrows. $x \ g$ and $y \ g$ are the masses of $R$ and $U$,respectively. (Molar mass of $H$,$C$,and $O$ are $1$,$12$,and $16 \ g \ mol^{-1}$ respectively). $(1)$ The value of $x$ is $(2)$ The value of $y$ is.

Which of the following is not a member of the same homologous series?