Question

6. a. You perform a titration using phenolphthalein indicator to determine the concentration of an

unknown acid (HA)(aq). When titrating with 0.5 M NaOH, you find the endpoint of a 10 mL sample
of HA (aq) after 7.6 mL of NaOH is dispensed from the buret. What is the concentration of HA(aq)? (6
pt)
HA + OH A + H₂O

Answer 1

Moles of NaOH = 0.5 M x 0.0076 L = 0.0038 mol

Moles of HA = 0.0038 mol

Concentration of HA = 0.0038 mol/0.01 L = 0.38 M