Question

Describe the construction and working of the Pycnometer.

Answer 1

Pycnometer (Density Bottle)

Purpose: To measure relative density.

Construction:

1. A pycnometer consists of a ground glass stopper with a fine hole through it.
2. When the bottle is filled and the stopper is inserted, the excess liquid rises through the hole and runs down outside the bottle.

Working:

1. The bottle will always contain the same volume of liquid at a constant temperature.
2. The density of the given volume of a substance to the density of the equal volume of a referred substance is called relative density or specific gravity of the substance.