Question

what are advantages of using hg than coal​

Answer 1

$\huge{\mathfrak{\underline{\underline{Answer :}}}}$

It is better to use Hg than alcohol because of the following reasons :-

Its B.P is 357°C and freezing point is -390 C.

Hence it can be used over range of temperature from -30° C to 300° C.

It can easily be obtained in the pure state.

Its expansion is nearly uniform over ordinary range of temperature.

It is practically non-volatile, hence vapours are not formed which could effect the expansion. Hence the reading is accurate.

It has low specific heat capacity.

It is an opaque and shining liquid and it does not wet the glass.