Which of the following is the major product in the following reaction?

Given below are two statements.
Statement $I :$ The presence of weaker $\pi$-bonds makes alkenes less stable than alkanes.
Statement $II :$ The strength of the double bond is greater than that of carbon-carbon single bond.
In the light of the above statements,choose the correct answer from the options given below.

$A$ hydrocarbon having molecular formula $C_5H_{10}$ produced a tertiary alcohol upon treatment with a few drops of conc. sulphuric acid and water. The same hydrocarbon when reacted with acidic potassium permanganate produced a ketone and a carboxylic acid. The hydrocarbon is $....$

Write the products of the addition reaction $ >C = C < + XY \to $

Product $(P)$ is

Rank the following alkenes in order of decreasing heats of hydrogenation (largest first):
$1$. $1-$butene
$2$. $2-$methyl$-2-$butene
$3$. trans$-2-$butene
$4$. cis$-2-$butene