Featured in PASCO’s College Chemistry Instructor Guide

College Chemistry Instructor Guide

(PS-3803A)

College Instructor edition with 36 experiments covering introductory and general chemistry topics.

Ka of a Weak Acid

Lab Summary

Use a pH sensor and drop counter to determine the equilibrium constant for the ionization of a weak acid to ascertain the identity of the acid.

Theory

Students determine the equilibrium constant for the ionization of a weak acid (Ka) to ascertain the identity of the acid.

Method

Students gain experience conducting the following procedures:

  • Determining the Ka of a weak acid by measuring the pH of a solution titrated halfway to the equivalence point.
  • Using a pH sensor.
  • Performing a titration.

Sensors / Equipment Used:

PASPORT Chemistry Sensor

(PS-2170)

Allows students to measure Temperature, pH/ISE/ORP, Absolute Pressure & Voltage in one sensor. For use with PASPORT Interfaces.

PASPORT High Accuracy Drop Counter

(PS-2117)

Is a professional drop counter that allows students to capture detailed titration data. For use with PASPORT Interfaces.

Materials Used:

Ring stand 
Clamp, right-angle 
Beaker, 100-mL - 2
Buret, 50-mL 
Graduated cylinder, 100-mL 
Funnel 
Magnetic stirrer and stir bar 
0.20 M Sodium hydroxide (NaOH) - 75 mL
Unknown weak acid solution (use acetic acid) - 50 mL
Buffer solutions, pH 4 and pH 10 - 10 mL

The Associated Bundle:

Advanced Chemistry Standard Sensor Bundle

(PS-2928A)

Contains the probeware for completing experiments in the College Chemistry lab manual.

Interface Required

This experiment may require software and an interface for data collection.