Question

Two Isomeric alkenes A and B having molecular formula, $C_5{H}_{9}Cl$ on adding $H_2$, A gives optically inactive compound while B gives a chiral compound. The two isomer are

• A. A is 3-chloro-1-pentene and B is 1-chloropentene
• B. A is 2-chloro-3-methyl-2-butene and B is 1- chloro-3-methyl-1-butene
• C. A is 3-chloro-2-pentene and B is 2-chloro-2-pentene
• D. A is 4-chloro-2-pentene and B is 4-chloro-1-pentene

Answer 1

The correct option is C

A is 3-chloro-2-pentene and B is 2-chloro-2-pentene

$C{H}_3-C{H}_2-\stackrel{Cl}{\stackrel{|}{C}}=CH-C{H}_3\underrightarrow{H_2}C{H}_{3}C{H}_2-\stackrel{Cl}{\stackrel{|}{CH}}-C{H}_2-C{H}_3$

3-Chloro-2-pentene(A) Optically inactive

$C{H}_{3}C{H}_2-CH=\stackrel{Cl}{\stackrel{|}{C}}-CH-3\underrightarrow{H_2}C{H}_{3}C{H}_2-C{H}_2-\underset{.}{\stackrel{Cl}{\stackrel{|}{CH}}}-C{H}_3$

2-Chloro-2-Pentene(B) Opticaly active