Arrange the following:
In increasing order of boiling point: C2H5OH, (CH3)2NH, C2H5NH2
Solution
The boiling points of compounds depend on the extent of H-bonding present in that compound. The more extensive the H-bonding in the compound, the higher is the boiling point. (CH3)2NH contains only one H−atom whereas C2H5NH2 contains two H-atoms. Then, C2H5NH2 undergoes more extensive H-bonding than (CH3)2NH. Hence, the boiling point of C2H5NH2 is higher than that of (CH3)2NH.
Further, O is more electronegative than N. Thus, C2H5OH forms stronger H−bonds than C2H5NH2. As a result, the boiling point of C2H5OH is higher than that of C2H5NH2 and (CH3)2NH.
Now, the given compounds can be arranged in the increasing order of their boiling points as follows:
(CH3)2NH < C2H5NH2 < C2H5OH
