question_answer

The total number of acylic isomers including the stereoisomers (geometrical and optical), with the molecular formula \[{{C}_{4}}{{H}_{7}}Cl\] is

A) 12                          

B)        11                          

C) 10     

D)        9

Correct Answer: A

Solution :

Twelve in all Six geometrical isomers (i) (ii) (iii) (iv)   (v)   (vi)   Two optical isomers (vii) \[C{{H}_{3}}-\underset{H}{\overset{Cl}{\mathop{\underset{|}{\overset{*|}{\mathop{C}}}\,}}}\,-CH=C{{H}_{2}}\] (viii) \[C{{H}_{3}}-\underset{Cl}{\overset{H}{\mathop{\underset{|}{\overset{*|}{\mathop{C}}}\,}}}\,-CH=C{{H}_{2}}\] Four structural isomers (ix) \[C{{H}_{2}}C{{H}_{2}}-\overset{Cl}{\mathop{\overset{|}{\mathop{C}}\,}}\,=C{{H}_{2}}\] (x) \[C{{H}_{3}}-\overset{C{{H}_{3}}}{\mathop{\overset{|}{\mathop{C}}\,}}\,=CHCl\] (xi) \[C{{H}_{3}}-\overset{C{{H}_{2}}Cl}{\mathop{\overset{|}{\mathop{C}}\,}}\,=C{{H}_{2}}\] (xii) \[ClC{{H}_{2}}-C{{H}_{2}}-CH=C{{H}_{2}}\]