How do you calculate boiling point of a solution?
You calculate the boiling point of a solution by first performing and experiment.
A simple and classic one:
Put your solution in a beaker.
Put the beaker on a tripod over a Bunsen Burner or some type of heating element.
Place a thermometer in it.
Record the temperature of the substance when the temperature stops rising on the thermometer.
We know that this is the boiling point because when a substance stops heating up, it has reached its maximum point at which it can be heated.