Study of the properties of acetic acid

In this article, we have discussed step-by-step procedure to perform CBSE Class 10 Science Practicals experiment Properties of acetic acid. It will help you understand the different properties of ethanoic acid viz, odour (smell), solubility in water, effect on litmus, reaction with sodium bicarbonate. Perform the experiment and compare the results.

Aim:

To study the following properties of acetic acid (ethanoic acid)-

  1. Odour (Smell)
  2. Solubility in water
  3. Effect on litmus
  4. Reaction with sodium bicarbonate

Materials required:

  1. Test tube
  2. Litmus paper
  3. Dropper
  4. Cork fit
  5. Test tube stand
  6. Water
  7. Beaker
  8. Acetic acid
  9. Sodium bicarbonate
  10. Distilled water
  11. Lime water (freshly prepared)

Theory:

The chemical name of acetic acid is ethanoic acid and has a chemical formula CH3COOH. The COOH group is called the carboxylic group which is responsible for the properties of ethanoic acid. This acid freezes at 16.6° C hence called as glacial acetic acid. It smells like vinegar and dissolves in water. It is a weak acid as it dissociates in water. It reacts with alcohol to obtain ester. It reacts with sodium bicarbonate to give carbon dioxide gas.

Procedure:

  • To determine the odour:

Step 1: Take a test tube of 10 mL.

Step 2: Add 5 mL of ethanoic acid into it

Step 3: Bring the test tube near your nose and smell it by wafting.

  • To check the solubility in water:

Step 1: Take a test tube of 20 mL.

Step 2: Add 2 mL of ethanoic acid to it

Step 3: Pour 10-15 mL of distilled water and mix it.

  • To determine the effect on litmus:

Step 1: Take a clean dropper

Step 2: Take a blue litmus paper

Step 3: Pour 2-3 drops of ethanoic acid on the litmus paper.

  • Reaction with sodium bicarbonate:

Step 1: Take a test tube of 5 mL.

Step 2: Add a pinch of sodium bicarbonate to it

Step 3: Pour 1 mL of dilute ethanoic acid in the test tube.

Step 4: To the mouth of the test tube fix a cork with bent delivery tube

Step 5: The other end of delivery tube is required to be dipped in lime water.

Observation and results:

PropertiesObservation
Determination of odourPungent/vinegar smell
Checking its solubility in waterDissolves in water
Determining the effect on litmusBlue litmus paper turns red
Reaction with sodium bicarbonateA colourless gas is produced which turns the lime water milky

Results:

  1. Ethanoic acid or acetic acid or glacial acetic acid smells like vinegar.
  2. Glacial acetic acid is water-soluble.
  3. Ethanoic acid turns blue litmus paper red.
  4. When acetic acid reacts with sodium bicarbonate, carbon dioxide gas liberated.

Precautions to be taken during the experiment:

  • Handle the solution with care.
  • Add a small amount of sodium bicarbonate.
  • Do not inhale the vapours of the chemicals.
  • Lime water should be freshly prepared.

Viva Voce:

1. The functional group present in ethanoic acid is _________.

Ans: Carboxylic group.

2. At what temperature glacial acetic acid freezes?

Ans: 16.6° C.

3. How do you determine if acetic acid is an acid?

Ans: During the litmus test, if the blue litmus paper turns red then it is said to have acidic properties.

4. Acetic acid is a strong acid. True or false?

Ans: False.

5. The alkyl group present in acetic acid is _______.

Ans: Methyl.