How much sodium hydroxide should you expect to use to reach the endpoint?

Question

You are trying to confirm that your bottle of hydrochloric acid is actually 1.5 M, as labeled. You decided to perform a titration with 1.0 M sodium hydroxide and 14.4 mL of your hydrochloric acid. How much sodium hydroxide should you expect to use to reach the endpoint?

Answer 1

HCl + NaOH ==> NaCl + H2O

Note the 1 : 1 mole ratio of HCl and NaOH

How many moles of HCl do you have?

14.4 ml x 1 L/1000 ml x 1.5 mol/L = 0.0216 moles HCl are present

How many moles of NaOH will you need?

You will need 0.0216 moles NaOH (1:1 mole ratio)

What volume of 1.0 M NaOH will you need?

(x L)(1.0 mol/L) = 0.0216 moles

x = 0.0216 L = 21.6 mls

You can also see this to be the answer by looking at the concentrations of HCl and NaOH. The HCl is 50% greater (1.5 M vs. 1.0 M) and so it will take 50% more volume. 14.4 ml x 1.50 = 21.6 mls.