JEE Main 2019 — Hydrocarbons Question with Solution
From: JEE Main 2019 (Online) 12th January Morning Slot
Question
The correct order for acid strength of compounds :
CH CH, CH3–C CH and CH2 = CH2 is as follows
CH CH, CH3–C CH and CH2 = CH2 is as follows
Choose an option
Show full solutionCorrect option: C
Correct answer
CHC CH > CH3 – C CH > CH2 = CH2
Step-by-step explanation
Among CH CH and CH2 = CH2, in CH CH compound H atom is attached with sp hybridised C atom and in CH2 = CH2 compound H atom is attached with sp2 hybridised C atom.
As we know, electronegitivity of sp carbon is more compare to sp2 carbon atom and that H is more acidic which is attached with more electronegative carbon atom. So CH CH is more acidic than CH2 = CH2.
Among CH CH and CH3–C CH, in CH CH both the H atom is connected to sp carbon atom but in CH3–C CH, with one sp carbon atom H atom attached and with other sp carbon atom -CH3 group attached which have +I effect and we know +I effect decreases acidic strength.
So, CH CH is more acidic than CH3–C CH.
So correct order is
HC CH > CH3 – C CH > CH2 = CH2
As we know, electronegitivity of sp carbon is more compare to sp2 carbon atom and that H is more acidic which is attached with more electronegative carbon atom. So CH CH is more acidic than CH2 = CH2.
Among CH CH and CH3–C CH, in CH CH both the H atom is connected to sp carbon atom but in CH3–C CH, with one sp carbon atom H atom attached and with other sp carbon atom -CH3 group attached which have +I effect and we know +I effect decreases acidic strength.
So, CH CH is more acidic than CH3–C CH.
So correct order is
HC CH > CH3 – C CH > CH2 = CH2
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This is a previous-year question from JEE Main 2019, covering the Hydrocarbons chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.