Single Choice

The decreasing order of boiling points of ethyldimethylamine, n- butylamine and diethylamine is n - Butylamine > Diethylamine > Ethyldimethylamine. This trend of the boiling point can be explained as:

Aboiling point increases with increase in molecular mass
Btertiary amines have highest boiling point due to highest basicity
Cintermolecular hydrogen bonding is maximum in primary amines and absent in tertiary amines
Correct Answer
Dintramolecular hydrogen bonding is present in tertiary amines

Solution

The decreasing order of boiling points:
n-butylamine(primary amine) > diethylamine(secondary amine) > ethyldimethylamine (tertiary amine).
$$ CH_3CH_2CH_2CH_2NH_2 > (C_2H_5)_2NH > C_2H_5NH(CH_3)_2$$
In primary amines only one hydrogen is substituted by an alkyl group, in secondary amines, two hydrogens are substituted by alkyl groups and in tertiary amines, all the three hydrogens are substituted by alkyl groups thereby resulting in the absence of intermolecular hydrogen bonding. Higher the hydrogen bonding difficult is to break the bonds thereby high boiling point.
Intermolecular hydrogen bonding is maximum in primary amines and absent in tertiary amines.

SIMILAR QUESTIONS

Organic Compounds Containing Nitrogen

The correct order of boiling points of the following isomeric amines is: $$C_4H_9NH_2.(C_2H_5)_2NH,\, C_2H_5N(CH_3)_2$$

Organic Compounds Containing Nitrogen

Give plausible explanation for each of the following: (i) Why are amines less acidic than alcohols of comparable molecular masses? (ii) Why do primary amines have higher boiling point than tertiary amines? (iii) Why are aliphatic amines stronger bases than aromatic amines?

Organic Compounds Containing Nitrogen

The correct order of boiling points of the following isomeric amines is: $$C_4H_9NH_2.(C_2H_5)_2NH,\, C_2H_5N(CH_3)_2$$

Organic Compounds Containing Nitrogen

The decreasing order of boiling points of ethyldimethylamine, n- butylamine and diethylamine is n - Butylamine > Diethylamine > Ethyldimethylamine. This trend of the boiling point can be explained as:

Organic Compounds Containing Nitrogen

Tertiary amines have lowest boiling points amongst isomeric amines because:

Organic Compounds Containing Nitrogen

Give plausible explanation for: Why do primary amines have higher boiling points than tertiary amines?

Organic Compounds Containing Nitrogen

Which of the following is/are correct?

Organic Compounds Containing Nitrogen

Give reasons for the following: Primary amines have higher boiling point than tertiary amines.

Organic Compounds Containing Nitrogen

Account for the following: Although trimethylamine and n-propylamine have the same molecular weight, but the former boils at a lower temperature (276K) than the latter (322K). Explain why.

Organic Compounds Containing Nitrogen

Which of the following compounds has the lowest boiling point?

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