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Home Chemistry Chemistry Class 9 To determine the boiling point of water
Chemistry Class 9 Lab Experiments

To determine the boiling point of water


To determine the boiling point of water.

Material Required

A beaker, a vertical stand, a thermometer, water, tripod stand, wire guaze, burner.


A liquid changes its state at a constant temperate called boiling point, to the vapour (or gaseous) state by absorbing real t energy. The boiling point of a liquid is its characteristic i.e. it is different for different liquids. Water boils at 100°C, so the boiling 1 point of waters is 100°C.


  1. Take a beaker. Pour some water in the beaker so as to fill it half. Place the beaker on a wire guaze placed over the tripod stand.
  2. Clamp a thermometer in a vertical stand and insert it in the beaker as shown in the .
  3. Heat the beaker over the flame of a burner and observe the temperature of water.
  4. The temperature of water rises continuously till the water starts boiling at 100°C. Now the bubbles formed through the entire volume of water are seen.
  5. Note the level of mercury in the thermometer by keeping your eye horizontal. This will give the boiling point of water.



The constant temperature at which water boils = 100°C


The boiling points of water is 100°C.


  1. The bulb of thermometer must not touch the base or walls of the beaker.
  2. The bulb of thermometer must remain immersed inside water.
  3. Record the temperature of water only when it becomes constant.