Finding Molarity of unknown solution

Question

You are given a solution of 0.670M NaOH and asked to find the molarity of an unknown HBr solution. 80.0 mL of NaOH was used to reach the endpoint when 25.5 mL of HBr was titrated. What is the molarity of the HBr solution?

Formula?

Answer 1

NaOH + HBr => NaBr + H₂O .. balanced equation

mols NaOH used = (0.080 L)(0.670 mol/L) = 0.0536 mol

mols HBr present = 0.0536 b/c is 1:1 in equation

Molarity of HBr = 0.0536 mol/0.0255 L= 2.10 M