Quick Summary
- Ethanol makes alcoholic drinks like beer, wine, and spirits
- Hospitals use it as antiseptic and medicine solvent
- Biofuel industry mixes ethanol with petrol to save costs
- Chemical factories use it to produce plastics, perfumes, and dyes
- Automobile radiators use it as antifreeze in cold weather
Main Uses of Ethanol
1. Alcoholic Beverages
The most common use of ethanol is in drinks consumed across Nigeria and worldwide. When yeast ferments sugar from grains, fruits, or tubers, it produces ethanol. Different drinks contain varying amounts:
| Beverage Type | Ethanol Content | Examples |
|---|---|---|
| Beer | 3-7% | Star, Gulder, Trophy |
| Wine | 9-16% | Palm wine, grape wine |
| Spirits | 20-50% | Gin, whisky, vodka, ogogoro |
The fermentation process stops naturally when ethanol concentration reaches about 15% because yeast cells die at higher levels. Distillation concentrates the alcohol further for spirits.
2. Medical and Pharmaceutical Applications
Nigerian hospitals and clinics use ethanol daily. Before injections, nurses rub ethanol (methylated spirit) on your skin to kill bacteria. The alcohol destroys bacterial cell walls quickly.
Drug manufacturers dissolve many medicines in ethanol. Cough syrups, tonics, and herbal extracts often contain 5-20% ethanol. It helps preserve the medicine and allows active ingredients to dissolve properly.
During COVID-19, hand sanitizers became essential. Most contain 60-70% ethanol mixed with glycerin and water. NAFDAC regulates these products to ensure safe ethanol levels.
3. Industrial Solvent
Ethanol dissolves substances that water cannot. Paint factories in Lagos use it to dissolve dyes and resins. Perfume makers in Onitsha blend it with essential oils to create fragrances.
The printing industry uses ethanol-based inks because they dry faster than water-based ones. When newspapers print at midnight for morning distribution, quick-drying ink saves time.
Ethanol also extracts plant compounds. Companies making natural products dissolve herbs and spices in ethanol, then evaporate it to get concentrated extracts.
4. Biofuel Production
Nigeria and Brazil lead in mixing ethanol with petrol. When you buy fuel at filling stations in some states, it may contain 10% ethanol (called E10). This blend reduces import costs since we can produce ethanol locally from cassava or sugarcane.
Ethanol burns cleaner than pure petrol. It releases less carbon monoxide, reducing air pollution in cities like Lagos and Port Harcourt. Some flex-fuel vehicles can run on 85% ethanol (E85).
The Federal Government promotes ethanol production to:
- Reduce dependence on imported petrol
- Support cassava farmers with new markets
- Create jobs in rural biofuel plants
- Lower transport costs across Nigeria
5. Chemical Manufacturing
Chemical factories use ethanol as a starting material for other compounds. When heated with concentrated sulphuric acid, ethanol produces ethene gas. Plastic manufacturers then convert ethene into polythene bags, bottles, and containers.
The reaction works like this:
C₂H₅OH → C₂H₄ + H₂O
(Ethanol converts to ethene and water at 170°C)
Other products made from ethanol include:
- Ethanoic acid: Used in vinegar and textile dyeing
- Esters: Sweet-smelling compounds in perfumes and flavors
- Ethyl ethanoate: Nail polish remover and glue solvent
- Diethyl ether: Previously used as surgical anesthetic
6. Antifreeze in Automobile Radiators
Although Nigeria has hot weather, this use matters for cold storage facilities and imported vehicles. Pure water freezes at 0°C, but ethanol freezes at -114°C. Mixing ethanol with radiator water lowers the freezing point.
In cold rooms storing fish or meat in Kano or Jos, ethanol prevents cooling system pipes from freezing and bursting. The mixture keeps equipment running even when temperatures drop below zero.
7. Laboratory and Research Uses
School laboratories and universities use ethanol as:
- Specimen preservative: Biology labs store animal organs in 70% ethanol to prevent decay
- Burner fuel: Spirit lamps provide clean flames for heating experiments
- Cleaning agent: Removes grease from glassware better than water
- Reagent: Used in many chemical tests and reactions
8. Cosmetics and Personal Care
Nigerian beauty products often contain ethanol. Check ingredient lists on:
- Perfumes and body sprays (60-90% ethanol)
- Aftershave lotions (cooling and antiseptic)
- Hair sprays (helps product dry quickly)
- Deodorants (kills odor-causing bacteria)
- Mouthwash (antibacterial properties)
The alcohol evaporates quickly from skin, leaving fragrance or active ingredients behind.
Why Ethanol Works So Well
Ethanol’s many uses come from its special properties:
| Property | Reason It Matters | Application |
|---|---|---|
| Dissolves many substances | Both polar and non-polar compounds dissolve | Perfumes, medicines, inks |
| Burns cleanly | Complete combustion with less smoke | Biofuel, spirit lamps |
| Evaporates quickly | Leaves no residue behind | Hand sanitizer, cleaning |
| Kills microorganisms | Destroys bacterial cell membranes | Antiseptic, preservative |
| Low freezing point | Stays liquid in cold conditions | Antifreeze |
| Mixes with water | Forms stable solutions | Beverages, medicines |
Ethanol Production in Nigeria
Nigeria can produce ethanol from local crops. The process involves fermenting starch or sugar:
- Cassava: Grind tubers, add enzymes to break starch into sugar, then ferment
- Sugarcane: Extract juice, add yeast, ferment for 2-3 days
- Corn: Similar to cassava processing
- Sweet sorghum: Grows well in northern Nigeria, produces sugar-rich stalks
After fermentation, distillation purifies the ethanol. Industrial ethanol reaches 95-99% purity for fuel and manufacturing.
Common Exam Mistakes
WAEC examiners report these frequent errors about ethanol uses:
- Confusing ethanol with methanol: Students write “methylated spirit is pure ethanol” but it actually contains toxic methanol added to prevent drinking. Know the difference.
- Wrong chemical formulas: Writing “C₂H₆O” instead of “C₂H₅OH” loses marks. The structural formula shows how atoms connect.
- Vague answers: Writing “used in industry” without specifying which industry or how. Always give specific examples like “solvent in paint manufacturing” or “raw material for plastic production.”
- Forgetting biofuel use: Many students only mention alcoholic drinks and antiseptic, missing the important fuel application tested in recent exams.
- Poor expression: WAEC wants clear English. Write “Ethanol kills bacteria on skin surfaces” not “It have the ability to be killing the bacteria.”
- Missing mark allocations: If a question says “State FOUR uses” (4 marks), listing six uses wastes time. Match your answer points to marks available.
Practice Questions
Multiple Choice Questions
1. Which property of ethanol makes it suitable as an antiseptic?
(a) It has a pleasant smell
(b) It evaporates quickly leaving no residue
(c) It destroys bacterial cell membranes ✓
(d) It mixes well with water
2. When ethanol is mixed with petrol in a 10:90 ratio, the fuel is called:
(a) E85
(b) Biodiesel
(c) E10 ✓
(d) Methanol fuel
3. What happens when ethanol is heated with concentrated H₂SO₄ at 170°C?
(a) It forms ethanoic acid
(b) It produces ethene gas ✓
(c) It burns completely
(d) Nothing happens
4. Why does ethanol work better than water as antifreeze?
(a) It is cheaper than water
(b) It has a much lower freezing point ✓
(c) It boils at a higher temperature
(d) It does not mix with water
Essay Questions
1. (a) State FOUR industrial uses of ethanol. (4 marks)
(b) Explain why ethanol is preferred over water as a solvent in perfume manufacture. (3 marks)
Answer tips: In part (a), simply list four different industries and specific uses. In part (b), mention that ethanol dissolves essential oils which are non-polar, evaporates quickly to leave fragrance, and does not support bacterial growth.
2. (a) Name TWO local Nigerian crops that can produce ethanol. (2 marks)
(b) Describe briefly how ethanol is obtained from one of these crops. (4 marks)
(c) Give TWO reasons why the Nigerian government encourages ethanol production. (2 marks)
Answer tips: Part (a) could include cassava, sugarcane, corn, or sweet sorghum. Part (b) needs a sequence: prepare crop → convert to sugar → ferment with yeast → distill. Part (c) should mention economic benefits like reducing fuel imports or supporting farmers.
3. A student wrote “Ethanol is used to make drinks, kill germs, and in factories.” The examiner gave only 1 mark out of 3. Explain what the student did wrong and rewrite the answer properly. (6 marks)
Answer tips: The student’s answer is too vague. Proper answers should specify “alcoholic beverages like beer and wine,” “antiseptic for disinfecting skin before injections,” and “solvent for dissolving dyes in paint manufacturing” or similar specific details.
Memory Aids
Remember ethanol’s main uses with “ABCDEF”:
- Alcoholic beverages (beer, wine, spirits)
- Biofuel (mixed with petrol as E10)
- Chemical manufacturing (making plastics from ethene)
- Disinfectant (kills bacteria in hospitals)
- Extracting solvent (dissolves perfumes, dyes, medicines)
- Freezing point reducer (antifreeze in cold systems)
For why ethanol works well: “DEBE”
- Dissolves both polar and non-polar substances
- Evaporates quickly
- Burns cleanly
- Eliminates bacteria
Related Topics
- Ethanol – General properties and structure
- Preparation of Ethanol – Fermentation and hydration methods
- Physical Properties of Ethanol – Boiling point, solubility, density
- Chemical Properties of Ethanol – Reactions with sodium, acids, oxidizing agents
- Organic Chemistry – Functional groups and homologous series