In the reaction $CH_3CH=CH_2 + H_2O + [O]$ $\xrightarrow{KMnO_4/Acid} CH_3-CH(OH)-CH_2(OH)$ $\xrightarrow{[O]} X + HCOOH$,what is $X$?

In the following reaction,$A$ and $B$ respectively are
$A \xrightarrow{HBr} C_2H_5Br \xrightarrow{B} A$

The main product of the following reaction $(1 \ mol)$ will be:
$C_6H_5-CH_2-CH=CH_2 + HBr \rightarrow \text{Products}$

The products $Q$ and $R$ in the following reactions respectively are:
$H_2 + CH_3-C \equiv CH$ $\xrightarrow{\text{Lindlar's catalyst}} P$ $\xrightarrow[Zn + H_2O]{O_3} Q + R$

An organic compound $X$ with molecular formula $C_{11}H_{14}$ gives an optically active compound on hydrogenation. Upon ozonolysis,$X$ produces a mixture of compounds $P$ and $Q$. Compound $P$ gives a yellow precipitate when treated with $I_{2}$ and $NaOH$ but does not reduce Tollen's reagent. Compound $Q$ does not give any yellow precipitate with $I_{2}$ and $NaOH$ but gives Fehling's test. The compound $X$ is:

The major product of the reaction of $2-$butene with cold alkaline $KMnO_4$ is: