Question
Why mercury is generally used as a liquid in barometer?
Solution
It is because of the following reasons:
(i) Mercury is non-volatile at ordinary temperature, therefore, the pressure exerted by the vapours above the mercury column is very small and can be neglected.
(ii) The height of the column in a barometer is inversely proportional to the density of the liquid. Since mercury is very dense, it is best for barometer as it supports column of convenient height.
