Question

Freezing point of mercury is:
[A] 100K
[B] 234.3K
[C] 123.5K
[D] 450K

Answer 1

HINT: Mercury is a 3d-transition metal. It is liquid at room temperature. Its freezing point is lower than any other stable element. Its density increases upon freezing.


COMPLETE STEP BY STEP SOLUTION: We know that freezing point is the temperature at which a liquid freezes. Every liquid has different freezing points depending upon its chemical properties.
Mercury is a chemical element and its atomic number is 80. In the periodic table, it is found in group 12, period 6. The third transition metal series ends with mercury. Mercury is denoted by the symbol ‘Hg’ in chemistry.
Mercury is a heavy, d-block element and it is the only metal which is liquid at standard temperature and pressure conditions. For this reason mercury is often termed as liquid metal.
Mercury is toxic for our body. It can even be absorbed through skin. Swallowing of mercury might cause mercury poisoning which results in chronic and acute poisoning.
Besides thermometers and manufacture of other mechanical and electrical tools, its property of forming amalgam is of great use in the medical industry. The amalgam is generally used as dental fillings.
Now let us discuss the freezing point of mercury.
Mercury freezes at a temperature far lower than any stable metal.
 It freezes at a temperature of $-{38.83}^{\circ }C$.
The options are given to us in units of kelvin so we have to convert Celsius to Kelvin.
We know that, $0^{\circ }$Celsius is equal to 273 kelvin.
Therefore, $-{38.83}^{\circ }C$ will be 273 + (-38.83) Kelvin that is 234.3 Kelvin.

Therefore, the correct answer is option [B] 234.3K


NOTE: Mercury is a shiny, silvery liquid metal. It has a very coefficient of expansion, i.e. it responds very efficiently to temperature change, even if the change is the slightest. It has lower boiling and freezing points than any stable element (except copernicium and flerovium). On freezing, the volume of mercury decreases by around 4% and its density changes from 13.69 g/cc to 14.184 g/cc. Solid mercury is malleable and ductile like any other metal.