Question

In an experiment to determine the boiling point of water, state reason for the following

precautions:-(i) The bulb of thermometer should not touch the sides of beaker.(ii) While boiling water, pumice stones should be added.

Answer 1

1) During boiling point measurement, temperature's bulb should not touch the sides of the beaker because in that case temperature of the glass of the beaker is measured instead of the solution. Thus, there will be error in the measurement.
2) 2-3 pieces of pumic stones are added during measurement to avoid bumping of the liquid when the temperature rises.