CHEMISTRY COMMUNITY

For 6B.11 a) ii), why do you multiply 0.18M by (500.0 ml/5.00 ml) and don't use the m1v1=m2v2 equation?

Please include the entire question with your post; this will better assist us in helping you

Chem_Mod wrote:Please include the entire question with your post; this will better assist us in helping you

The question is:
A student added solid Na2O to a volumetric flask of volume 200.0 mL, which was then filled with water, resulting in 200.0 mL of NaOH solution. Then 5.00 mL of the solution was transferred to another volumetric flask and diluted to 500.0 mL. The pH of the diluted solution is 13.25. (a) What is the molar concentration of hydroxide ions in (i) the diluted solution, (ii) the original solution? (b) What mass of Na2O was added to the first flask?