Ethanol - Properties and Uses - UNSOLVED PRACTICE SET
Chapter: Carbon and Its Compounds | Topic: Ethanol Properties and Uses
ETHANOL - PROPERTIES AND USES - UNSOLVED PRACTICE SET
Topic: Ethanol Properties and Uses
Multiple Choice Questions
Q1. The molecular formula of ethanol is:
- CH₃OH
- C₂H₅OH
- C₃H₇OH
- CH₃COOH
Q2. Ethanol is commonly prepared by the fermentation of:
- Glucose
- Proteins
- Fats
- Minerals
Q3. Which of the following is a physical property of ethanol?
- It is a solid at room temperature
- It is insoluble in water
- It is a colourless liquid with a pleasant smell
- It has a boiling point of 200°C
Q4. Ethanol reacts with sodium metal to produce:
- Sodium ethanoate and hydrogen
- Sodium ethoxide and hydrogen
- Sodium hydroxide and ethane
- Sodium carbonate and water
Q5. Which of the following is NOT a use of ethanol?
- As a solvent in medicines
- As a fuel in cars
- As a preservative for biological specimens
- As a building material
Q6. The process of making ethanol from sugar solution using yeast is called:
- Distillation
- Fermentation
- Hydrogenation
- Saponification
Short Answer Questions
Q7. Write the structural formula of ethanol. Identify the functional group present in it.
Q8. Why is ethanol considered a renewable source of energy? Explain with reference to its production from sugarcane.
Q9. What happens when ethanol is heated with concentrated sulphuric acid at 443 K? Write the chemical equation and name the product.
Q10. Why is ethanol mixed with petrol to form gasohol? Mention one advantage of using gasohol.
Q11. Your school uses ethanol-based sanitizers at the entrance. Explain why ethanol is effective in killing germs. Why is it mixed with water instead of being used pure?
Q12. Write two chemical properties of ethanol.
Long Answer Questions
Q13. Describe the manufacture of ethanol by the fermentation of sugar. Write the chemical equation. What conditions are necessary for fermentation? Why is the temperature maintained between 25°C and 35°C?
Q14. Explain the following properties of ethanol with chemical equations:
(a) Reaction with sodium metal
(b) Dehydration by concentrated sulphuric acid
(c) Oxidation to ethanoic acid
(d) Combustion in air
Also mention two important uses of ethanol in everyday life.
Q15. During a science project, you decide to make biofuel from sugarcane juice at home (under adult supervision).
(a) Name the microorganism used for fermentation.
(b) Why is anaerobic condition necessary for this process?
(c) How would you separate ethanol from the fermentation mixture?
(d) Why is ethanol considered a better fuel than petrol in terms of environmental impact?
Numerical / Application-Based Problems
Q16. The molecular formula of ethanol is C₂H₅OH.
(a) Calculate its molecular mass. (Atomic masses: C = 12, H = 1, O = 16)
(b) Calculate the percentage of oxygen in ethanol.
(c) How many moles of ethanol are present in 9.2 g of ethanol?
Q17. In a fermentation experiment, 180 g of glucose (C₆H₁₂O₆) is converted into ethanol.
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂
(a) Calculate the mass of ethanol produced. (Molar masses: Glucose = 180 g/mol, Ethanol = 46 g/mol)
(b) Calculate the volume of CO₂ produced at STP. (1 mole of gas = 22.4 L at STP)
(c) Why is the yield of ethanol never 100% in this process?
Q18. A car runs on gasohol, which is a mixture of petrol and ethanol. The fuel tank contains 40 litres of gasohol with 10% ethanol by volume.
(a) Calculate the volume of ethanol in the fuel tank.
(b) If ethanol produces 30% less carbon monoxide than petrol during combustion, calculate the percentage reduction in CO emission if the car used pure ethanol instead of petrol.
(c) Why is ethanol-blended petrol promoted by the Indian government?