Hello!
I believe it is called Condensation
Condensation is when the water vapor (gas) in the air turns into a liquid. (Like the fog on a mirror after you take a hot shower)
In the given examples, Cl2 and CCl4 are non-polar and held by covalent bonds. HI and H2O are polar molecules and held by ionic bonds.
Since covalent bonds are weaker than ionic bonds, Cl2 or CCl4 must have the lowest melting points. Among the two, Cl2 has a lower molecular mass than CCl4, hence Cl2 must have the lowest melting point.
Ans A) Cl2
