You have molarity and you have volume. Use the formula :
Molarity(M)= Moles(N)/Liter(L) to get the solution.
450 ml= .450 L
.250 = N/.450
N=.1125 moles of NaOH.
And since you know the moles, use the molar mass to figure out the grams.
(40g/mol NaOH) x (.1125 mol) =
4.5g of NaOH.
Hope it helps. Good luck on chemistry.
