Molarity or molar concentration is a measure of the concentration of a chemical species, of a solute in a solution, using as units, number of moles, and volume in liters. The formula for Molarity is:
M = n/V
Where:
n = number of moles
V = volume in Liters
We have:
n = 2.7 moles of NaCl
V = 0.450 Liters of solution
Now we add these values into the formula
M = 2.7/0.450
M = 6.0 M is the molarity