I'm pretty sure the answer is that the normal boiling point means the substance is under "normal" or standard conditions. So the boiling point of the substance at a pressure of 1 ATM or 760 torr...
The Boiling Point is the point at which a substance at liquid state boils. The temperature that the liquid has to reach to be at Boiling Point (B.P) ranges, it is different for each liquid. The B.P...
Alcohol is almost every substance that has OH group. [of course except acids and carbohydrates, but that's not the point]. So the boiling point will be different according to length of carbon chain....