The labeled diagram is given in the image attached.
As it can be seen from the image that freezing is when energy is removed from the system at 0 ⁰ while melting is when energy is added at 0⁰.
Also when energy is added at 100⁰C, it causes boiling while when it is removed at 100⁰C, it causes condensation.
Melting point of water is 0⁰C while boiling point is 100⁰C
So let's convert this amount of mL to grams:
Then we need to convert to moles using the molar weight found on the periodic table for mercury (Hg):
Then we need to convert moles to atoms using Avogadro's number:
So now we know that in 1.2 mL of liquid mercury, there are present.