Question

You wish to perform a simple distillation to purify a compound with a boiling point of 235 °C. In order to avoid unwanted decomposition that can occur at such high temperatures, you wish to perform your distillation at a lower temperature. How can you change the conditions of the distillation you perform to efficiently accomplish this goal? Explain how your change will produce the desired effect.

Answer 1

To do the distillation of a liquid at below its boiling temperature we need to reduce the pressure. Generally a liquid boils at a temperature at which the vapor pressure of liquid is equal to atmospheric pressure. If we increase the temperature the vapor pressure of the liquid increases at a certain temperature vapor pressure of liquid is equal to atmospheric pressure then liquid starts to boil. This temperature is called normal boiling point of that liquid.

If we want to boil the liquid before its boiling point then pressure should be reduced. Then liquid will get that pressure at a temperature which is less than its boiling temperature.