The reaction of trans-but$-2-$ene with $Br_2$ in $CCl_4$ yields products. The number of stereoisomeric products $(X)$ formed is:

The stability order of the given alkenes is

Two alkenes,$X$ ($91\%$ yield) and $Y$ ($9\%$ yield),are formed when the following compound is heated:
The structures of $X$ and $Y$,respectively,are:

Dehydration of ethanol gives

An alkene $(A)$ $C_{16}H_{16}$ on ozonolysis gives only one product $(B)$ $C_8H_8O$. $(B)$ can also be obtained by the hydrolysis of the product obtained from the reaction between cyanobenzene and $CH_3MgBr$. $(A)$ shows geometrical isomerism and decolourises $Br_2$ water. $(B)$ on treatment with $SeO_2$ produces $(C)$. Which statement is not correct about $(A)$?

What is the major product obtained from the debromination of meso-$2,3$-dibromobutane?