You have molarity and you have volume. Use the formula :
Molarity(M)= Moles(N)/Liter(L) to get the solution.
150 ml= .150 L
7.7 = N/.150
N=.1.155 moles of NaOH.
And since you know the moles, use the molar mass to figure out the grams.
(40g/mol NaOH) x (1.155mol) =
46.2 g of NaOH.
