JEE Main 12 Jan 2019 Morning Question 22
Question: The correct order for acid strength of compounds $ CH\equiv CH,CH _3-C\equiv CH $ and $ CH _2=CH _2 $ is as follows [JEE Main Online Paper Held On 12-Jan-2019 Morning]
Options:
A) $ CH _3-C\equiv CH>CH\equiv CH>CH _2=CH _2 $
B) $ CH _3-C\equiv CH>CH _2=CH _2>HC\equiv CH $
C) $ HC\equiv CH>CH _3-C\equiv CH>CH _2=CH _2 $
D) $ CH\equiv CH>CH _2=CH _2>CH _3-C\equiv CH $
Show Answer
Answer:
Correct Answer: C
Solution:
As the s-character of $ CHbond $ increases, acidity increases.
Thus, acidity order $ \underset{\begin{smallmatrix} sP \\ (50) \end{smallmatrix}}{\mathop{CH\equiv CH>}},\underset{\begin{smallmatrix} sP^{2} \\ (33.3) \end{smallmatrix}}{\mathop{CH _2=CH _2}}, $ +1 effect ( $ -CH _3 $ group) reduces acidity Thus,
acidity order will be $ CH\equiv CH>CH _3-C\equiv CH>CH _2=CH _2 $
