posted by Jack .
How much volume(mL)of 2.50 M NaOH(aq)must be added to 25.0 mL of water to produce a 1.50 M NaOH solution?
c1v1 = c2v2
c = concn
v = volume
Then subtract the 25.0 mL to find volume that must be added. And the volume that must be added is IF the volumes are additive.