What is the molarity of a solution made by diluting exactely 10.00 mL of a 0.1235 M solution of KNO3 to exactely 250 mL in a graduated flask?
Who knows if you use a graduated flask for measuring the volume. But I assume that isn't the problem. Use the dilution formula of c1v1 = c2v2
c = concn
v = volume.