Which of the following is a correct decreasing order of boiling points of the given isometric compounds:
Ethyldimethyl amine (I), n-butylamine (II), Diethylamine (III)
Which of the following is a correct decreasing order of boiling points of the given isometric compounds:
Ethyldimethyl amine (I), n-butylamine (II), Diethylamine (III)
The correct option is C II>III>I
Answer:
Primary amine has higher boiling point than
secondary followed by tertiary amine, this is because higher boiling
points of the primary amines is that they can form hydrogen
bonds with each other as well as van der Waals dispersion forces and
dipole-dipole interactions.
Tertiary amine has no hydrogen left for
forming Hydrogen bonds among themselves so can not show intermolecular
H-bonding. So intermolecular force will be weak and low boiling point
of tertiary amines
I=Ethyldimethyl amine=30
II=n−butylamine=10
III=diethylamine=20
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.
So order of boiling points will be
II>III>I
Answer:
Primary amine has higher boiling point than secondary followed by tertiary amine, this is because higher boiling points of the primary amines is that they can form hydrogen bonds with each other as well as van der Waals dispersion forces and dipole-dipole interactions.
Tertiary amine has no hydrogen left for forming Hydrogen bonds among themselves so can not show intermolecular H-bonding. So intermolecular force will be weak and low boiling point of tertiary amines
I=Ethyldimethyl amine=30
II=n−butylamine=10
III=diethylamine=20
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.
So order of boiling points will be II>III>I
Choose the correct decreasing order of stablity: 
