JEE Main · 2023 · 01 Feb 2023 · Shift 1 · Hydrocarbons

$Na/liq\mathrm{N}{\mathrm{H}}_3$ reduces but-2-yne to $trans$-but-2-ene ($B$); ${\mathrm{H}}_2/Pd\text{-}\mathrm{C}$ gives $cis$-but-2-ene ($A$). $A$ ($cis$) has a net dipole and is polar; $B$ ($trans$) is symmetric with zero dipole. Statement (C) is self-contradictory — it says $A$ is more polar \emph{because} its dipole moment is zero — so (C) is incorrect. Statement (D) has no valid basis since $\mathrm{B}{\mathrm{r}}_2$ adds readily to both alkenes. Statements (A) and (B) are correct. The incorrect statements are therefore (C) and (D), but no option lists exactly $\{C,D\}$; hence the question is a bonus with no correct option.