Question

why do you why do we use mercury in the thermometer can water be used instead of Mercury what are the problems in using it

Answer 1

hey there!!
$\red{MERCURY}$:-
it is only single metal which remains in liquid state at the temperature of room.

$\textbf{ why\: do \:we\: use \:mercury\: in\: the\: thermometer}$:-
becoz MERCURY has a high coefficient of expantion no other metal or nonmetal is equal to MERCURY in suspension so slightest change in temperature can be observed with its help .

No we can't use water in thermometer in place of MERCURY becoz we Can't notice adject state of temperature with water or any othrr metal or nonmetal which i have told earlier

hope u liked.
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Answer 2

heyy!!!mate here is your answer

Mercury has some special properties to be used as a liquid in thermometer they are.

=It's expansion is uniform +for equal amounts of heat is expands by equal length s

it is opaque and shining
it doesn't stick to the sides of the glass tube.
it is a good conducter of heat.
it is easily available in pure states

Demerits in using water....
we cannot take the correct reading as water is colour less.
The expansion of water is not uniform

hope it will be helpful to you...