NEET Solved Paper 2018 Question 17
Question: Hydrocarbon [A] reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon atoms. [A] is [NEET - 2018]
Options:
A) $ C{H_3}\text{-C}{H_3} $
B) $ C{H_2}\text{=C}{H_2} $
C) $ CH\equiv CH $
D) $ C{H_4} $
Show Answer
Answer:
Correct Answer: D
Solution:
$\begin{aligned} R-H + Br_2 & \xrightarrow{\text{Substitution}} R-Br + HBr \ R-Br + 2Na & \xrightarrow[\text{Wurtz reaction}]{} R-R + 2NaBr \end{aligned} $
In the substitution reaction, alkanes produce alkyl bromides.
In the Wurtz reaction, two alkyl halides react with sodium (Na) metal to form a higher alkane.
Since after the Wurtz reaction, the gaseous hydrocarbon has less than 4 carbon atoms, ‘R’ should contain only 1 carbon atom.
So, ‘A’ is $ C{H_4} $.
