To determine the strength of a weak acid (acetic acid) and a strong acid (hydrochloric acid) in a mixture using conductometric titration with a strong base (sodium hydroxide).

• Conductivity meter or conductometer
• Burette (50 mL)
• Pipette (10 mL)
• Beaker (100 mL)
• Magnetic stirrer and stir bar (optional)
• Sodium hydroxide (NaOH) solution (0.1 M)
• Mixture of acetic acid (CH₃COOH) and hydrochloric acid (HCl)
• Distilled water

Theory

Conductometric titration measures the change in electrical conductivity of a solution as a titrant (NaOH) is added. The conductivity changes due to the replacement of ions during the neutralization reactions:

1. Neutralization of HCl (strong acid):
   • HCl fully dissociates in water, contributing a high concentration of H⁺ ions, which are replaced by less conductive Na⁺ ions during titration, causing a decrease in conductivity.


2. Neutralization of CH₃COOH (weak acid):
   • After HCl is neutralized, NaOH reacts with acetic acid, which is weak and partially dissociates. As the Na⁺ replaces H⁺ ions and acetate ions (CH₃COO^-) form, the conductivity will increase after reaching a minimum point.

By plotting conductivity against the volume of NaOH added, the titration curve will show two distinct equivalence points corresponding to the neutralization of HCl and CH₃COOH.