Give two reasons why acetamide has a higher boiling point than water?

In this question we have to get the reasons to have higher melting point of acetamide (CH₃CONH₂) than that of water (H₂O).

The reasons are-

1. The molecular weight of acetamide is more than that of water.

2. Acetamide can form strong dimeric six (6) member intermolecular hydrogen bond.

We know the boiling point of a compound depends upon its molecular weight, as the molecular weight increases the melting point also increases. In case of acetamide the molecular weight is 59 g/mol whereas for water it is 18 g/mol. Thus the boiling point of acetamide should be more than water.

There is a strong effect of hydrogen bond on the boiling point of a compound. As the strength of the hydrogen bond between the molecules of a compound increases the boiling point also increases. Now between water and acetamide both form hydrogen bond as shown in figure 1 and 2 respectively.

But the hydrogen bond between the acetamide molecules are strong six membered hydrogen bond than the chain hydrogen bond found in water as shown in the figure.    

the correct answer would be d. hope this !