Match the words in the column to the appropriate blanks in the sentences. a. negative
b. liquid
c. positive
d. solid
The phase with the greater density is argon because the liquid slope of the solid/liquid equilibrium line (also called the fusion curve) is meaning that an increase in pressure on argon will result in the formation of argon.

Explanation:

A phase diagram is a graphical representation with axes, representing temperature and pressure, showing the equilibrium conditions of a given substance to be a solid, liquid, or gas.

From the information given, the substance here is Argon.

So, the phase diagram of Argon can be seen in the image below.

From the diagram, it is obvious that the slope of the fusion curve is positive. Hence, the density of the solid argon will be greater than that of the liquid argon.