How many mL to titrate?

Question

How many mL of LiOH 2.666 M do you need to titrate 18.0 mL of 1.50 M H3PO4

Answer 1

H₃PO₄ + 3 LiOH ==> Li₃PO₄ + 3H₂O ... balanced equation

moles H₃PO₄ present = 18.0 ml x 1 L/1000 ml x 1.50 mol/L = 0.027 moles

moles LiOH needed = 0.027 moles H₃PO₄ x 3 moles LiOH/mol H₃PO₄ = 0.081 moles LiOH

(x L)(2.666 mole/L) = 0.081 moles

x = 0.03038 L x 1000 ml/L = 30.38 mls = 30.4 mls LiOH needed (to 3 significant figures)