Titration & Electrochemistry Experiments: A Comprehensive Guide

Posted on Aug 27, 2024 in Chemistry

Titration and Electrochemistry Experiments

Acid-Base Titrations

3. Titration of Strong Acid with NaOH

This experiment involves titrating a strong acid (hydrochloric acid) with a strong base (sodium hydroxide).

  1. Measure 10ml of an unknown HCl solution into a titrating flask.
  2. Add 3 drops of methyl orange indicator.
  3. Fill a buret with 0.1 N NaOH.
  4. Titrate the unknown HCl until the color changes to radish-yellow.
  5. Repeat the experiment twice.
  6. Use the mean value for calculations.

4. Titration of Acetic Acid with NaOH

This experiment involves titrating a weak acid (acetic acid) with a strong base (sodium hydroxide).

  1. Measure 10ml of acetic acid solution into a titrating flask.
  2. Add 3 drops of phenolphthalein indicator (colorless in acidic solutions, red in basic solutions).
  3. Fill a buret with 0.1 N NaOH.
  4. Titrate the unknown acetic acid solution until the color becomes red.
  5. Repeat the measurement twice and calculate the mean value.

5. Titration of Gastric Fluid

This experiment determines the free hydrochloric acid content in gastric fluid.

  1. Measure 20ml of gastric juice into three titration flasks.
  2. Put 2-3 drops of methyl red into each titration flask.
  3. Titrate the gastric fluid until the color changes to yellow. Record the amount of NaOH used (VA). This indicates the free HCl content.
  4. Add three drops of phenolphthalein.
  5. Continue the titration with NaOH until the solution turns pink.
  6. Record the amount of NaOH used (VA). Repeat the titration two more times.

Electrometric Titration

6. Principles of Electrometric Titration of Phosphoric Acid

This experiment involves determining the changing pH when a weak acid (phosphoric acid) is titrated with a strong base (NaOH) using a pH meter.

  1. Measure 50ml of acetic acid or phosphoric acid into two 100ml beakers. Place magnetic stir bars in each beaker.
  2. Fill the buret with NaOH.
  3. Add NaOH in 0.5ml portions, noting the pH from the pH meter after each addition. Wait until the pH stabilizes before recording.
  4. Continue until adding more NaOH does not cause a significant change in pH.

Redox Titration (Permanganometry)

8. Permanganometry: Principles and Factorization of Titrating Solution

This experiment introduces the principles of permanganometry and the standardization of a potassium permanganate (KMnO4) solution using oxalic acid or its soluble salts.

9. Permanganometry: Determination of Fe2+ Concentration

This experiment involves determining the concentration of Fe2+ using a standardized KMnO4 solution.

  1. Dissolve 10ml of Mohr’s salt [Fe(NH4)(SO4)2 • 6H2O] in three flasks.
  2. Add a few pieces of MnSO4 to each solution.
  3. Fill the buret with standardized KMnO4 solution.
  4. Titrate until the color turns purple-violet (the endpoint is indicated by the excess KMnO4).

Complexometric Titration

12. Complexometric Titration: Determination of Unknown Cu2+ Concentration

This experiment determines the concentration of Cu2+ using EDTA as a chelating agent.

  1. Add 10ml of CuSO4 solution to a flask.
  2. Add 10ml of distilled water and NH3 (under a fume hood).
  3. Add sodium murexide as an indicator.
  4. Shake well to dissolve the contents.
  5. Titrate with EDTA until the original violet color returns.

13. Complexometric Titration: Determination of Ca2+ and Mg2+ Concentration

This experiment determines the concentration of Ca2+ and Mg2+ in a solution using EDTA.

  1. Add 10ml of the unknown solution containing Ca2+ and Mg2+ to a flask.
  2. Add 10ml of distilled water and 10% NaOH.
  3. Add solid murexide as an indicator and shake well.
  4. Titrate with EDTA until the color changes from rose to violet.
  5. Degrade the murexide with HCl until the color disappears.
  6. Add ammonia solution and eriochrome black T indicator.
  7. Titrate with EDTA until the color changes from reddish-brown to dark blue.

Conductometry

14. Measurement of Specific Conductance in Acetic Acid Solution

This experiment introduces the principles of conductometry and the determination of specific conductance using a conductivity meter.

15. Determination of the Ionization Constant of Acetic Acid by Conductometry

This experiment involves determining the ionization constant of acetic acid through conductivity measurements at various dilutions.

Spectrophotometry

16. Spectrophotometry: Determination of the Absorption Spectrum of Phenol Red

This experiment involves determining the absorption spectrum of phenol red and plotting a calibration curve for the dissociated form.

17. Spectrophotometric Determination of the Ionization Constant of Phenol Red

This experiment involves determining the ionization constant of phenol red using spectrophotometric measurements at different pH values.

Electrochemistry

18. Electrochemistry: Measurement of the Electromotive Force of the Daniell Cell

This experiment involves measuring the electromotive force (EMF) of a Daniell cell and studying the effect of electrolyte concentration on the EMF.

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