KVPY PROBLEMS (PREVIOUS YEARS)

$2, 3$-Dibromobutane can be converted to $2$ -butyne in a two-step reaction using:

In the reaction of $1$ -bromo-$3$-chlorocyclobutane with two equivalents of sodium in ether, the major product is

The reaction of an alkene $\mathrm{X}$ with bromine produces a compound $\mathrm{Y}$, which has $22.22\% \mathrm{C}$, $3.71\% \mathrm{H}$ and $74.07\% \mathrm{Br}.$ The ozonolysis of alkene $\mathrm{X}$ gives only one product. The alkene $\mathrm{X}$ is $[$Given: atomic mass of $\mathrm{C}=12; \mathrm{H}=1; \mathrm{Br}=80]$

In the following reaction ${\mathrm{H}}_3\mathrm{C}-\mathrm{C}\equiv \mathrm{C}-\mathrm{H}\underset{{\mathrm{H}}_3{\mathrm{O}}^{+}}{\overset{{\mathrm{Hg}}^{2+}}{\to }}\mathrm{X}\underset{\mathrm{PhCHO}}{\overset{\mathrm{diINaOH}}{\to }}\mathrm{Y}$ $\mathrm{X}$ and $\mathrm{Y}$, respectively, are

Among the following reactions, a mixture of diastereomers is produced form

The major product of the following reaction sequence

 is

A solution of $20.2 \mathrm{g}$ of $1, 2$ -dibromopropane in $\mathrm{MeOH}$ upon heating with excess $\mathrm{Zn}$ produces $3.58 \mathrm{g}$ of an unsaturated $\mathrm{X}$. The yield $(\%)$ is closest to [Atomic weight of $\mathrm{Br}$ is $80$]

The compound shown below

can be readily prepared by Friedel-Crafts reaction between