The number of $sp^3$ hybridized carbon atoms in cyclohexene is

Product $(P)$ is

The reaction of $1,3$-butadiene with $1$ equivalent of $HBr$ at different temperatures yields products $A$ and $B$. Identify the relationship between $A$ and $B$. The reaction scheme is as follows:
$CH_2=CH-CH=CH_2 + HBr (1 \text{ eq}) \xrightarrow{25^{\circ}C} A$
$CH_2=CH-CH=CH_2 + HBr (1 \text{ eq}) \xrightarrow{-80^{\circ}C} B$

The incorrect method for the synthesis of alkenes is:

Write the structures and $IUPAC$ names of the different structural isomers of alkenes corresponding to the molecular formula $C_5H_{10}$. How many such isomers are possible?

The reaction of $HBr$ with $CH_3-C(CH_3)=CH_2$ in the presence of peroxide will give: