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Ethanol and ethanoic acid have similar names, two carbon atoms each, and reactions that look alike on paper. In the exam and in the lab, you need to keep them apart. This post lists every reaction NCERT gives, works through three balancing and mass checks, and shows which lab test actually distinguishes the two.
What does the 2026-27 syllabus ask for?
The CBSE Class X Science curriculum for 2026-27 lists "Ethanol and Ethanoic acid (only properties and uses), soaps and detergents" under Carbon and its Compounds. Its practical list includes studying the odour, solubility in water, effect on litmus and reaction with sodium hydrogencarbonate of acetic acid. The text is section 4.4 of NCERT's Carbon and its Compounds (Class 10, Reprint 2026-27).
How do the two compare?
Formula: ethanol CH₃CH₂OH; ethanoic acid CH₃COOH.
Common name: alcohol; acetic acid.
Melting and boiling points (NCERT Table 4.1): ethanol 156 K and 351 K; acetic acid 290 K and 391 K.
Everyday form: ethanol in tincture iodine, cough syrups and tonics; a 5 to 8% solution of acetic acid is vinegar.
Acidity: ethanol is not an acid; ethanoic acid is a weak acid, unlike HCl, which is completely ionised.
Pure ethanoic acid freezes at 290 K, about 17 °C, which is why it is called glacial acetic acid.
What are ethanol's reactions?
With sodium: 2Na + 2CH₃CH₂OH → 2CH₃CH₂ONa + H₂. The products are sodium ethoxide and hydrogen.
Dehydration: heating ethanol at 443 K with excess concentrated sulphuric acid gives ethene and water. The acid acts as a dehydrating agent.
Oxidation: alkaline potassium permanganate or acidified potassium dichromate oxidise ethanol to ethanoic acid.
Combustion: ethanol burns in air to give carbon dioxide and water.
What are ethanoic acid's reactions?
Esterification: with ethanol and an acid catalyst, it gives a sweet-smelling ester, ethyl ethanoate (CH₃COOC₂H₅), and water.
Saponification: the ester with sodium hydroxide gives back ethanol and sodium ethanoate.
With a base: NaOH + CH₃COOH → CH₃COONa + H₂O.
With carbonates and hydrogencarbonates: 2CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O + CO₂, and CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂.
Worked example 1: balance the combustion of ethanol
NCERT asks you to balance CH₃CH₂OH + O₂ → CO₂ + H₂O.
Carbon: 2 on the left, so 2CO₂.
Hydrogen: 6 on the left, so 3H₂O.
Oxygen on the right: 2 × 2 + 3 = 7. Ethanol supplies 1, so O₂ must supply 6, which is 3O₂.
Answer: C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O.
Worked example 2: vinegar and baking soda
Using atomic masses C = 12, H = 1, O = 16 and Na = 23, the molecular masses are CH₃COOH = 60, NaHCO₃ = 84, CH₃COONa = 82, H₂O = 18 and CO₂ = 44. Check: 60 + 84 = 144 and 82 + 18 + 44 = 144. Mass is conserved.
Now sample numbers: 30 g of vinegar at 5% contains 1.5 g of acid. It reacts fully with 1.5 × 84/60 = 2.1 g of baking soda and gives 1.5 × 44/60 = 1.1 g of carbon dioxide.
Worked example 3: the ester
CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O. Masses: 60 + 46 = 106 on the left and 88 + 18 = 106 on the right.
Which lab tests distinguish them?
Litmus: ethanoic acid turns blue litmus red; ethanol does not.
Sodium hydrogencarbonate: only the acid gives CO₂.
Smell: the acid smells of vinegar.
Sodium metal is not a good test. Ethanol gives hydrogen with sodium, and so do acids, so both can fizz.
Which mistakes cost marks?
Calling ethanoic acid a strong acid.
Writing H₂ as the gas from acid and hydrogencarbonate. It is CO₂.
Forgetting the conditions for dehydration: hot, concentrated H₂SO₄ at 443 K.
Mixing up the two reverse reactions: esterification makes the ester; saponification breaks it with an alkali.
A safety note
NCERT warns that even a small amount of pure ethanol can be lethal, that methanol in very small quantities can cause death and blindness, and that industrial ethanol is "denatured" with methanol and a blue dye so it is not drunk. Do the sodium reaction only as a teacher's demonstration, as NCERT says.
A practice routine
Write all eight reactions from memory, with conditions.
Redo the three worked examples with new sample numbers.
Practise naming related compounds using our Class 10 carbon compounds guide.
If balancing still feels like guesswork, the Fermi Problem Library has a step-by-step solver that explains the reasoning rather than printing an answer.
Tonight, balance the combustion of methanol the same way and check that the oxygen count matches.
