Chemistry, Acid-Base Titration

Question

.0500 L of HCl are placed in an Erlenmeyer Flask. 40.05 mL of 0.250M NaOH are added to the buret to reach the end point. What is the concentration of HCl in the Erlenmeyer Flask?

Answer 1

For this titration the balanced equation is HCl + NaOH ==> NaCl + H₂O

moles NaOH needed to neutralize the HCl = 40.05 ml x 1L/1000 ml x 0.250 mol/L = 0.0100 moles NaOH

moles HCl present = 0.0100 moles HCl

Concentration of HCl = 0.0100 moles/0.0500 L = 0.200 M (to 3 significant figures)