The correct order of basicity of amines in water is which of the following?
Answer & explanation
Correct answer: option 1
The correct answer is OPTION 1 - (CH3)2NH > CH3NH2 > (CH3)3N
The correct answer is Option 1 :
$$(CH_3)_2NH > CH_3NH_2 > (CH_3)_3N$$
In aqueous solution, the basicity of amines depends on:
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+I effect of alkyl groups, which increases electron density on nitrogen.
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Solvation of the protonated amine ion by water.
Secondary amines have strong +I effect and still get effectively solvated, making them the most basic in water.
Tertiary amines, although having a stronger +I effect, suffer from steric hindrance and poor solvation of the protonated ion, so their basicity decreases.
Hence, the order of basicity in water is:
$$(CH_3)_2NH > CH_3NH_2 > (CH_3)_3N$$