Identify the product $A$ in the following reaction:
$Methylenecyclohexane \xrightarrow{Br_2 / H_2O} A$

Addition of $HCl$ to $3,3$-dimethyl-$1$-butene yields two products,one of which has a rearranged carbon skeleton. Among the following carbocations,select the possible intermediates in that reaction:
$1.$ $(CH_3)_3C-C^+H-CH_3$
$2.$ $(CH_3)_3C-CH_2-C^+H_2$
$3.$ $(CH_3)_2C(Cl)-C^+(CH_3)_2$
$4.$ $(CH_3)_2C^+-CH(CH_3)_2$

Which major product is obtained by the addition of $1 \ mol$ of $HCl$ to $1,3$-butadiene at low temperature ($0^{\circ}C$ or below)?

The chemical reaction is shown below:
$C_6H_5-CH_2-CH=CH_2 + HCl \rightarrow X$,$X$ is:

An organic compound $(A)$ on ozonolysis followed by treatment with zinc dust and water gives product $(P)$,which can be used to preserve biological specimens. Identify $(A)$.

The reaction of propene with $H_3O^{+}$ proceeds through which of the following intermediates?