Chemistry HELPPPPP!!!?

Question

Please Help:

What volume of 0.27 M Sodium hydroxide is needed to reactc with 29.5 ml of 0.55 M phosphoric acid.

Ok I know the answer is 180ml I just dont know how my teacher got that.

Answer 1

29.5mL H3PO4 x 0.55molH3PO4/1000mL H3PO4 x 3molNaOH/1mol H3PO4 x 1000mL NaOH/0.27molNaOH = (29.5)(0.55)(1000)(3)/(0.27)(1000) =

Start with the 29.5mL. Multiply by 0.55mol/1000mL, the mL cancel, and you get molH3PO4.

Multiply next by 3molNaOH/1molH3PO4 to get molNaOH. That comes from the balanced equation, 3NaOH + H3PO4 ===> Na3PO4 + 3H2O. The molH3PO4 cancel, and you get molNaOH.

Next multiply by 1000mL NaOH/0.27molNaOH to get the answer. The molNaOH cancel the molNaOH.