$3$

$16.$ What is the major product of the following reaction?

$17.$ What is the most best reagent to convert ierr$-$butyl alcohol to tert$-$butyl chloride?

A$)HS{O}_{3}Cl$

B$)C{H}_{3}MgCl$

C$)HCl$

D$)AlC{l}_3$

$18.$ What is the major product of the following reaction?

$19.$ What is the comect name for the following compound??

A$)($R$)-1-$methyl$-1-$cyclohexen$-4-$ol

B$)($S$)-1-$methyl$-2-$cyclohexen$-4-$ol

C$)(R)-4-$methyl$-3-$cyclohexen$-1-$ol

D$)(5)-4-$methyl$-3-$cyclohexen$-1-$ol

$20-$ Which of the following is the best deseription for the $C=N$ bond?

A$)$ The two bonds results from $s{p}^2(C)-s{p}^2(N)$ overlap

B$)$ The two bond's results from $s{p}^3(C)-s{p}^2(N)$ overlap

C$)$ The two bonds are of same property

D$)$ One bond is from $s{p}^2(C)-s{p}^{\text{'}}(N)$ and the other from $p(C)-p(N)$ orbitals

$21-$ For which of the following cycloalkancs is cis$-$trans isonerism possible?

A$)$ isobutylcyclopentane

B$)$ ethylcyclopentane

C$)1-$ethyl$-1-$methyl$-$eyclopentane

D$)1-$ethyl$-2-$methylcyclopentane