Question

Mercury is used in thermometer because:
A.It does not wet glass
B.It expands on heating
C.It is liquid
D.All of these

Answer 1

Hint:We must know that a chemical element with atomic number 80 and with a chemical symbol $Hg$ is mercury. It is known as quicksilver. It is liquid metal and belongs to d-block elements.

Complete step by step answer:
We know that a clinical thermometer is a device that is used to measure human body temperature. It is made up of long glass tubes that are graduated.
A thermometric liquid is present inside the tube that expands proportionally to temperature, and the reading is measured.
We can use mercury as thermometric liquid because
It expands uniformly on heating.
The specific heat capacity of mercury is low.
The boiling point of mercury is high $\left( {{{357}^ \circ }\,C} \right)$ and the melting point of mercury is low $\left( { - {{39}^ \circ }C} \right).$
It is a good conductor of heat.
It does not wet the glass tube walls.
It appears shiny, opaque and is visible through naked eye.
It is present in pure form.

Option (D) is correct because mercury does not stick to the walls of the glass tube, on heating; it expands and appears in liquid state.

Note:
We know that the majority of the metals are solids except mercury, which is liquid at room temperature and are good conductors of heat and electricity because of its high expansion coefficient. Due to this high expansion coefficient, mercury expands at greater rate and can be used as thermometric liquid within a thermometer. In addition, the smallest change in temperature is notable when mercury is used in the thermometer due to its high expansion coefficient.