Question

2. What effect does each of the following have on a simple distillation and/or the boiling point that one determines in the laboratory? a. lower atmospheric pressure b. higher atmospheric pressure c. heating the distillation vessel too rapidly d. not adding a boiling stone or stirrer to the distillation vessel

Answer 1

The boiling point is the temperature when the vapor pressure of the liquid becomes equal to the atmospheric pressure. So, under standard conditions the pressure is 760 atm, and so the vapors fight to attain that pressure only then they can leave the liquid surface and that situation will be known as boiling. The liquid will keep moving out of the vessel at fix rate.

a) when the atmospheric pressure is lower as in hilly regions (for example 755 atm) then, vaopur will reach this value at lower temperature and so will boil soon.

b) this is the opposite of what said above

c) heating distillation too rapidly can break the glass also expands upon heating. Slow heating maintains thermal equilibrium quickly.

d) boiling stones have rough surface due to which bubbles can easily form and they promote even boiling and these bubbles prevent over boiling.