2 interactive concept widgets for Amines. Drag any slider, change any number, and watch the formula and the answer update live. Built so you understand how each NEET problem actually works, not just the final number.
Visual pKb bar chart for 11 amines from diethylamine (pKb 3.02) to p-nitroaniline (pKb 13.0). Click any amine to see the inductive effect, solvation, and resonance explanation for its basicity. Covers the counter-intuitive 2° > 1° > 3° order in water.
Amine Basicity Comparator
Compare pKb values across aliphatic and aromatic amines. Click any compound to see the inductive, solvation, and resonance effects that determine its basicity. The key NEET fact: aliphatic amines (pKb 3-4) are 10⁶× more basic than aniline (pKb 9.4) because of resonance delocalisation.
pKb Comparison (lower pKb = stronger base)
(C₂H₅)₂NH
3.02
(CH₃)₂NH
3.27
C₂H₅NH₂
3.25
CH₃NH₂
3.36
(CH₃)₃N
4.22
NH₃
4.74
CH₃-C₆H₄-NH₂
8.92
C₆H₅NH₂
9.4
Cl-C₆H₄-NH₂
9.85
O₂N-C₆H₄-NH₂
13
(C₆H₅)₂NH
13.2
Stronger base (low pKb)Weaker base (high pKb)
Dimethylamine
(CH₃)₂NH
2° Aliphatic
pKb = 3.27 | Kb = 5.4 × 10⁻⁴
Inductive effect (+I / -I)+I from 2 methyl groups. Good electron donation to N.
Solvation of conjugate acid2 N-H bonds available in conjugate acid (CH₃)₂NH₂⁺. Good solvation.
Resonance / delocalisationNone. Lone pair fully localised on N.
NEET Key PointMost basic among the simple aliphatic amines in water. This is a frequently tested NEET point — the answer is NOT trimethylamine.
Why this pKb: Best balance of inductive effect and solvation. 2 methyl groups donate electrons (+I), and the conjugate acid still has 2 N-H bonds for hydrogen bonding with water. This combination makes it the most basic simple amine in aqueous solution.
Golden Rules for NEET
Aliphatic vs aromaticAliphatic amines (pKb 3–4) are ~10⁶× more basic than aniline (pKb 9.4). Resonance in aniline kills the lone pair.
Order in water: 2° > 1° > 3°For aliphatic amines, dimethylamine beats trimethylamine because better solvation of (CH₃)₂NH₂⁺ (2 N-H) outweighs the extra +I from the 3rd methyl.
EDG increases, EWG decreasesp-CH₃ on aniline ring increases basicity; p-NO₂ dramatically decreases it (extended conjugation withdraws lone pair).
More aryl groups = weakerDiphenylamine (2 rings) < aniline (1 ring). Each ring delocalises the lone pair further.
Amine distinction tests simulator
Select amine class (1°, 2°, 3°) and test (Hinsberg, carbylamine, HNO₂). Shows the observation, mechanism explanation, and conclusion for each combination. Covers all three NEET distinction tests in one widget.
Amine Distinction Tests Simulator
Select an amine class (primary, secondary, or tertiary) and a distinction test (Hinsberg, carbylamine, or HNO₂). See what happens, why it happens, and what conclusion you can draw. Covers all three tests that NEET uses to identify amine type.
RNH₂ reacts with C₆H₅SO₂Cl to give RNH-SO₂C₆H₅ (monosubstituted sulfonamide). This product has ONE acidic N-H (pKa ~10). It dissolves in excess KOH: RNH-SO₂C₆H₅ + KOH → RN⁻-SO₂C₆H₅ K⁺ + H₂O (alkali-soluble). On acidification, the sulfonamide reprecipitates. KEY: 1° sulfonamide dissolves in alkali but 2° does not — this is the distinguishing observation.
Complete Summary Table
Test
1° Amine
2° Amine
3° Amine
Hinsberg (PhSO₂Cl + KOH)
Alkali-soluble sulfonamide
Alkali-insoluble ppt.
No reaction
Carbylamine (CHCl₃ + KOH)
Foul smell (isocyanide)
No reaction
No reaction
HNO₂ (NaNO₂ + HCl, 0°C)
Ar: diazonium salt; Alkyl: N₂ gas
Yellow N-nitrosamine
Salt (reversible)
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