Question

Water takes longer time to boil than alcohol because water has :

• A. a higher specific heat capacity.
• B. a smaller molecular weight
• C. a lower specific heat capacity
• D. polar covalent bonds
• E. a larger molecular weight

Answer 1

The correct option is D polar covalent bonds

Due to polar covalent bonds in water, it has a slight positive charge at one end of the molecule and a slight negative charge at the other (a polar molecule). Oxygen atom attracts electrons a little more strongly than hydrogen does. So even though the electrons from each atom are attracted by both the oxygen and the hydrogen, the electrons are a bit more attracted to the oxygen. This means that electrons spend a bit more time at the oxygen end of the molecule. This makes the oxygen end of the molecule slightly negative. Since the electrons are not near the hydrogen end as much, that end is slightly positive. When a covalently bonded molecule has more electrons in one area than another, it is called a polar molecule.

This makes the water molecules more tightly bound, and thus water as higher boiling point.