Question

You determine the concentration of a solution of HCl by titration with NaOH. The titration reaction is:

HCl(aq) + NaOH(aq) → H2O(l) + NaCl(aq)

Using a volumetric pipet, you transfer 10.00 mL of the HCl solution into an Erlenmeyer flask, then dilute it with ~50 mL of water and add 3 drops of phenolphthalein. The endpoint is reached after you have added 44.00 mL of 0.1250 M NaOH solution from a buret.

How many moles of HCl were in the original 10.00 mL sample of HCl?

a. 0.01250 moles

b. 0.005500 moles

c. 5.500 moles

d. 0.1250 moles