Experiment 24: Study Propoerties of Ethanoic acid


  • Study ethanoic acid


Materials required:

  • Sodium hydrogencarbonate
  • sodium hydroxide solution
  • phenolphthalein solution
  • conc. sulphuric acid
  • 5% ethanoic acid/ acetic acid
  • blue litmus paper strips
  • four test tubes
  • delivery tube

Observations and Findings:





Add 1 mL of the given sample of acid in 2 mL water.



Smell the sample 

Vinegar-like smell

Litmus test

Put a drop of ethanoic acid over a (i) blue litmus paper and (ii) red litmus paper

Blue litmus turned red; No change in red litmus

Reaction with

Take 1 mL of the ethanoic acid and add to it a pinch of sodium hydrogen-carbonate.

Effervescence (CO2 is liberated)

Reaction with NaOH(aq)

Take 5 mL of the ethanoic acid and add 2-3 drops of phenolphthalein solution to it. Then add sodium hydroxide solution to the mixture drop by drop. Shake the mixture gently. Count the number of drops of sodium hydroxide needed for appearance of pink colour in the reaction mixture.

 Solution turns pink once neutralization reaction is complete


  • Ethanoic acid is a mild acid. 5% solution of ethanoic acid is called vinegar and used to preserve food items



  • Ethanoic acid (CH3COOH) is an organic acid containing (-COOH) functional group.
  • It has an odour of vinegar. It turns blue litmus paper red and reacts with (a) sodium hydrogencarbonate to evolve carbon dioxide gas
    CH3COOH (l) + NaHCO3 (s) --> CH3COONa (aq) + CO2 (g) + H2O (l)
    (b) sodium hydroxide to produce sodium ethanoate and water.
    CH3COOH + NaOH (aq) --> CH3COONa (aq) + H2O
  • Acetic acid is an organic compound with the formula CH3COOH. It is a carboxylic acid consisting of a methyl group that is attached to a carboxyl functional group. The systematic IUPAC name of acetic acid is ethanoic acid and its chemical formula can also be written as C2H4O2. Vinegar is a solution of acetic acid in water and contains between 5% to 20% ethanoic acid by volume. The pungent smell and the sour taste is characteristic of the acetic acid present in it. An undiluted solution of acetic acid is commonly referred to as glacial acetic acid. It forms crystals which appear like ice at temperatures below 16.6oC. It has a wide range of applications as a polar, protic solvent. In the field of analytical chemistry, glacial acetic acid is widely used in order to estimate substances that are weakly alkaline.