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