An Overview of Class 10 Chemistry Properties Of Acetic Acid Experiment
Chemistry Experiment - Properties Of Acetic Acid Experiment
Acetic acid is also known as ethanoic acid, vinegar acid, ethylic acid, and methane carboxylic acid. It is a clear, organic, colourless liquid with a pungent odour similar to household vinegar. It has a variety of uses, including as raw material and solvent in the preparation of other chemical products, oil and gas production, and food and pharmaceutical industries.
Table of Contents
Aim
Apparatus Required
Theory
Procedure
Observation Table
Results
Aim
To study or determine the following properties of acetic acid or ethanoic acid-
Smell or Odour
Effect on litmus
Solubility in water
Reaction with sodium bicarbonate
Materials Required
Test tube
Beaker
Dropper
Litmus paper
Test tube stand
Distilled water
Acetic acid
Cork fit
Water
Sodium bicarbonate
Freshly prepared lime water
Theory
Acetic acid
The chemical name of acetic acid is ethanoic acid, and it has the chemical formula CH3COOH. The COOH group is called the carboxylic group, which is responsible for the properties of ethanoic acid. It smells like vinegar and dissolves in water.
Glacial Acetic acid
The acetic acid that contains a very little amount of water that is less than 1% is called anhydrous or water-free acetic acid or glacial acetic acid. Its melting point is 16.6 °C. The reason it is called glacial is that it solidifies into solid acetic acid crystals just cooler than room temperature at 16.6 °C, which is ice.
Procedure
To determine the odour:
Take a test tube of measurement 10 mL.
Then add 5 mL of ethanoic or acetic acid to it
Bring the test tube near or close your nose and smell it by wafting it.
To check the solubility in water:
Take a test tube of measurement 20 mL.
Then add 2 mL of ethanoic or acetic acid to it
Pour 10-15 mL of distilled water and stir or mix it.
To determine the effect on litmus:
Take a clean (well-washed) dropper
Take a blue litmus paper
Pour 2-3 drops of ethanoic or acetic acid on the litmus paper.
Reaction with sodium bicarbonate:
Take a test tube of measurement 5 mL.
Add a pinch of sodium bicarbonate to it
Then pour 1 mL of dilute ethanoic or acetic acid into the test tube.
To the mouth of the test tube, fix a cork with a bent delivery tube
The other end of the delivery tube is required to be dipped in lime water.
Observations
Result
Acetic acid or ethanoic acid or glacial acetic acid smells like vinegar.
Both acetic acid and glacial acetic acid are water-soluble.
Acetic acid turns blue litmus paper to red colour.
And, when acetic acid reacts or combines with sodium bicarbonate, carbon dioxide gas is liberated or released.
Precautions
Handle the solutions carefully.
Add a small amount of sodium bicarbonate.
Stay away from the vapours of the chemicals and try not to inhale them.
Lime water must be freshly prepared.
Lab Manual Questions
What are the other names for acetic acid?
Ans. Acetic acid is also known as ethanoic acid, vinegar acid, ethylic acid, and methane carboxylic acid.
How to measure the amount of acetic acid in vinegar?
Ans. We can calculate or measure the percent of acetic acid in vinegar by the given formula- \[\left( {\dfrac{{Mass\,of\,Acetic\,Acid}}{{Mass\,of\,Vinegar}}} \right) \times 100\].
In an experiment, one mole of acetic acid signifies.
Ans. One mole of acetic acid signifies the given amount or given mass of acetic acid is exactly equal to its molar or molecular mass.
How to take the acetic acid test?
Ans. We can take the acetic acid test by taking a blue litmus paper. If the solution turns the blue litmus to red, then the solution will be considered acetic acid.
Viva Questions
Name the functional group present in acetic acid.
Ans. Carboxylic acid is the functional group present in acetic acid.
Acetic acid: which types of acid, strong or weak?
Ans. Acetic acid is a weak acid.
At what temperature does glacial acetic acid freeze?
Ans. Glacial acetic acid freezes at 16.6 °C.
Name the alkyl group present in acetic acid.
Ans. The Methyl group is present in acetic acid.
Does acetic acid turn which colour of litmus to which colour?
Ans. Acetic acid turns blue litmus to red colour.
How to measure the amount of acetic acid in the vinegar?
Ans. To measure, the amount of acetic acid in vinegar can vary, typically between 4 to 6% for table vinegar, but up to three times higher (18%) for pickling vinegar.
Which gas is released when acetic acid reacts with sodium bicarbonate?
Ans. Carbon dioxide gas is released when acetic acid reacts with sodium bicarbonate.
What is the density of acetic acid in liquid form?
Ans. In the liquid form, the density of acetic acid is 1.049 g/cm³.
What is the boiling temperature of acetic acid?
Ans. The boiling temperature for acetic acid is 391K.
Practical Questions
The most preferred and usable form of acetic acid is-
Glacial acetic acid
Vinegar
Acetic anhydride
Chloroacetic acid
Ans. Vinegar is the most preferred and most usable form of acetic acid.
The pH value of vinegar is-
2.5
5
7
3.5
Ans. The pH value of vinegar is generally 3.5.
Name the form of acetic acid which forms an ice-like solid when the temperature is reduced-
Vinegar
Acetic anhydride
Glacial acetic acid
Chloroacetic acid
Ans. Glacial acetic acid is the form of acetic acid which forms an ice-like solid when the temperature is reduced.
When acetic acid reacts with metal ions, it liberates-
Acetic anhydride
Acetate salts
Chloroacetic acid
None of these
Ans. The formation of acetate salts takes place when acetic acid is exposed to the metal ion.
The malt vinegar can be prepared with the help of-
Acetate salts
Acetic acid
Fruit juice
Malted grain
Ans. The malt vinegar can be prepared from the malted grain.
Which of the following is the weak acid?
Acetic acid
Nitric acid
Hydrochloric acid
Sulphuric acid
Ans. Acetic acid is a weak acid, rest are strong acids.
Does acetic acid dissolve in water?
True
False
Not applicable
None of these
Ans. Acetic acid dissolves in water. So, it is true.
Acid releases, which ions in an aqueous solution.
H+ ions
OH- ions
No ions
None of these
Ans. Acid releases H+ ions in the aqueous solution.
Conclusion
From the above experiment, we can conclude that acetic acid has a pungent or vinegar-like smell, it turns blue litmus paper to red, it is soluble in water, and on reacting with sodium bicarbonate it releases carbon dioxide gas.
FAQs on Class 10 Chemistry Properties Of Acetic Acid Experiment
1. What are the key physical properties of acetic acid that a student would observe in a Class 10 experiment?
In a Class 10 experiment, a student would observe the following key physical properties of acetic acid (ethanoic acid):
- Odour: It has a sharp, pungent smell, very similar to that of vinegar.
- Appearance: It is a colourless liquid at room temperature.
- Solubility: It is completely miscible with water in all proportions, forming a clear, homogeneous solution.
- Taste: It has a distinct sour taste, characteristic of acids. (Note: Tasting chemicals in a lab is strictly forbidden).
2. What is the expected observation when a student adds a pinch of sodium bicarbonate to acetic acid? Write the balanced chemical equation for this important test.
When a pinch of solid sodium bicarbonate (NaHCO₃) is added to acetic acid (CH₃COOH), a brisk effervescence is observed. This is due to the rapid evolution of carbon dioxide (CO₂) gas. This test is a crucial indicator for the presence of a carboxylic acid group.
Balanced Chemical Equation:
CH₃COOH(aq) + NaHCO₃(s) → CH₃COONa(aq) + H₂O(l) + CO₂(g)
3. How does acetic acid affect blue and red litmus paper, and what important conclusion can be drawn from this observation?
When a drop of acetic acid is placed on moist blue litmus paper, the paper turns red. There is no change observed when it is applied to red litmus paper. This observation is a fundamental test which concludes that acetic acid is acidic in nature.
4. Why is ethanoic acid (acetic acid) considered a weak acid, even though it turns blue litmus red? This is an important concept for board exams.
Ethanoic acid is classified as a weak acid because it does not dissociate completely in water to release all its hydrogen ions (H⁺). It establishes an equilibrium in solution where most of the acid remains as undissociated CH₃COOH molecules. In contrast, strong acids like HCl dissociate completely. While it produces enough H⁺ ions to turn blue litmus red, its concentration of H⁺ ions is much lower than that of a strong acid of the same concentration.
5. What is the functional group present in acetic acid? How does this group influence the chemical properties studied in the experiment?
The functional group present in acetic acid is the carboxyl group (-COOH). This group is responsible for all the characteristic acidic properties observed in the experiment. It is the hydrogen atom of the -COOH group that is released as an H⁺ ion in water, making the substance an acid. This functional group is also the site of reaction with sodium bicarbonate and alcohols (esterification).
6. From an exam perspective, how can you distinguish between acetic acid and ethanol using a chemical test prescribed in the CBSE syllabus?
To distinguish between acetic acid and ethanol, the sodium bicarbonate test is the most reliable method from the syllabus.
- Observation with Acetic Acid: Upon adding sodium bicarbonate, there will be a brisk effervescence due to the release of carbon dioxide gas.
- Observation with Ethanol: Upon adding sodium bicarbonate, there will be no reaction or effervescence, as ethanol is neutral and does not react with weak bases like NaHCO₃.
This test provides a clear and distinct observation to identify the acidic nature of acetic acid.
7. Describe the esterification reaction, an important chemical property of acetic acid. Mention the reactants and reaction conditions.
Esterification is a key reaction where acetic acid (a carboxylic acid) reacts with an alcohol (like ethanol) in the presence of a catalyst to form a sweet-smelling compound called an ester.
- Reactants: Acetic acid (CH₃COOH) and Ethanol (C₂H₅OH).
- Reaction Conditions: The reaction is typically warmed gently in the presence of a few drops of concentrated sulphuric acid (H₂SO₄), which acts as a catalyst and a dehydrating agent.
- Observation: The resulting product, ethyl ethanoate (an ester), has a characteristic fruity or sweet smell.
Equation: CH₃COOH + C₂H₅OH --(Conc. H₂SO₄)--> CH₃COOC₂H₅ + H₂O
8. What is glacial acetic acid? Why is it named so, and how is it different from the solution used in school experiments?
Glacial acetic acid is the name for pure, water-free (anhydrous) acetic acid. It gets its name because it freezes at a relatively high temperature of 16.6°C (289.6 K), forming ice-like crystals in cool weather. The dilute solution used in school labs is typically a 5-8% solution of acetic acid in water, commonly known as vinegar, which is much less corrosive and safer to handle.
9. For a 3-mark question, list three important uses of acetic acid in industries or daily life.
Three important uses of acetic acid are:
- As a Food Preservative: A dilute solution of acetic acid, known as vinegar, is widely used as a preservative in pickles and as a flavouring agent in sauces and salads.
- Industrial Solvent and Reagent: It is used as a solvent in the manufacturing of plastics like cellulose acetate and as a starting material for synthesising esters, dyes, and pharmaceuticals.
- Coagulant in Rubber Industry: It is used to coagulate latex in the production of natural rubber.
10. A student observes that when they mix acetic acid and water, the test tube feels slightly warm. Why does this happen?
The mixing of acetic acid with water is an exothermic process. This means that heat is released when the strong hydrogen bonds are formed between the acetic acid molecules and water molecules. The energy released during the formation of these new bonds is greater than the energy required to break the existing bonds within pure water and pure acetic acid, resulting in a net release of heat and a slight increase in the temperature of the solution.
