question_answer

                2-bromopentane is heated with potassium ethoxide in ethanol. The major product obtained is:  

A)                 2-ethoxypentane           

B)                 pentene-1                         

C)                 trans-pentene-2             

D)                 cis-pentene-2

Correct Answer: C

Solution :

                \[C{{H}_{3}}-\underset{\begin{smallmatrix}  | \\  Br  \\  \text{2-bromopentane} \end{smallmatrix}}{\mathop{CH}}\,-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{3}}\xrightarrow{{{C}_{2}}{{H}_{5}}{{O}^{-}}{{K}^{+}}}\]                 \[C{{H}_{3}}-\overset{+}{\mathop{C}}\,H-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{3}}\,\frac{(-B{{r}^{-}})}{-{{H}^{+}}}\]