Answer:
0.750 M
Explanation:
Mass of NaOH [tex]= 39.97 gm\\[/tex]
Number of moles in 90 gm of NaOH
[tex]= 90 gm (\frac{Number of moles }{39.97})\\ = 2.250 mole\\Molarity = \frac{number of moles}{Volume of solution} \\= \frac{2.25}{3.00} \\= 0.750 Moles /litre\\[/tex]