M1V1 =M2V2
Where M1 and M2 is the molarity of the first and second solution respectively.
And V1 and V2 is teh volume of the first and tehs econd solution respecyively.
Molarity = No of moles/ 1 L of solution
No of moles = mass of the substance/molar mass of the substance
No of moles of potassium acid phthalate = 0.1495/204.227 = 0.00073 moles
Thus the same number of moles of NaOH is required in order to reach the equivalence point.
As Molarity = No of moles/ 1 L of solution
Molarity of NaOH solution = (0.00073/42.59) x 1000= 0.017 M