No
Magnesium Chloride is MgCl2
The method I use to name ionic compounds is 'swap and drop'
Mg oxidation number is +2 and Cl oxidation number is -1
Mg^2+ Cl^-1
'swap'
Mg^1 Cl^2
'drop'
MgCl2
Moles = n/v where n is the moles of solute and v being the liters of solution.
We can put in the information provided to find the molarity.
Moles = .45/3.0 = .15
So we now know that the molarity of that solution is .15!
I hope I helped you :). Make sure to memorize that formula because it's not that hard as long as you know what to plug in.