What is the number of $\sigma$ bonds in $1$-butene?

An alkene $'A'$ on ozonolysis gives a mixture of ethanal and pentan$-3-$one. Write the structure and $IUPAC$ name of $'A'$.

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:

Alkenes convert into alcohols by:

For the reaction given below,which of the following is not a possible product?
$H_2C=CH_2 + Br_{2(aq)} \xrightarrow{NaCl} \text{Products}$

Give the major product of the reaction: