JEE PYQ: Hydrocarbons Question 13
Question 13 - 2021 (26 Feb Shift 1)
For the given reaction:
$\text{CH}_2=\text{CHBr} \xrightarrow{1.\ \text{NaNH}_2}$ $\xrightarrow{2.\ \text{Red hot Fe tube},\ 873\text{ K}}$ (A) (major product)
What is ‘A’?
(1) $\text{CH}=\text{CH}-\text{NH}_2$ (vinylamine)
(2) 1,3,5-Trimethylbenzene (mesitylene)
(3) Styrene
(4) $\text{CH}_3\text{CH}_2\text{CH}_2\text{NH}_2$
Show Answer
Answer: (3)
Solution
$\text{CH}_3-\text{CH}=\text{CH}(-\text{Br}) \xrightarrow{\text{NaNH}_2}$ $\text{CH}_3-\text{CH}\equiv\text{CH}$ (propyne). Red hot Fe tube at 873 K causes trimerization of propyne to give mesitylene (1,3,5-trimethylbenzene).
BETA
