JEE Main 2014ChemistryGeneral Organic ChemistryEasyMCQ

JEE Main 2014General Organic Chemistry Question with Solution

JEE Main 2014 (06 Apr)

Question

Considering the basic strength of amines in an aqueous solution, which one has the smallest pKb value?

Choose an option

Show full solutionCorrect option: A
Correct answer
ACH3NH

Step-by-step explanation

Since in aromatic amines the lone pair undergoes delocalisation, aliphatic amines are more basic than aromatic amines.
Ph-NH2<R-NH2
In an aliphatic amine, due to the +I effect of -CH3 the order will be 3°>2°>1°.
In an aqueous solution, H-bonding takes place. So, the order will be 1°>2°>3°.

However, the resultant basic order is due to a mixture of both the effects(+I and hydrogen bond). So, the order is 2°>3°>1°

So, the final basic order is 

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About this question

This is a previous-year question from JEE Main 2014, covering the General Organic Chemistry 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.