The number of possible organobromine compounds which can be obtained in the allylic bromination of $but-1-ene$ with $N-bromosuccinimide$ $(NBS)$ is

Reaction $(1): CH_3-CH=CH-CH_3$ $\xrightarrow{\text{Cold } KMnO_4} (A)$ $\xrightarrow{NaIO_4} (B)$ ($2$ moles)
Reaction $(2): CH_3-CH=CH-CH_3 \xrightarrow{KMnO_4/NaIO_4} (C)$ ($2$ moles)
Product $(B)$ and $(C)$ respectively are:

In the following reaction $CH_3-C(CH_3)_2-CH=CH_2 \xrightarrow{H_2O/H^{+}} A \text{ (major)} + B \text{ (minor)}$,the major product $A$ is:

Draw the $cis$ and $trans$ structures of $hex-2-ene$. Which isomer will have a higher $b.p.$ and why?

The gas liberated at the anode by the electrolysis of a concentrated aqueous solution of dipotassium succinate is:

$A \xleftarrow[\Delta]{Cu} CH_3CH_2OH \xrightarrow[\Delta]{Al_2O_3} B$. $A$ and $B$ respectively are