Questions about Esters (Organic Chemistry)
20 multiple-choice questions about Esters (Organic Chemistry), each with five alternatives (A–E). The correct answers and extended explanations are provided at the end.
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Multiple Choice Questions: Esters (Organic Chemistry)
1. What is the general structure of an ester?
A) R–COOH
B) R–CO–R'
C) R–COO–R'
D) R–CH₂OH
E) R–NH₂
2. What two types of compounds react to form an ester?
A) Alcohol and ketone
B) Carboxylic acid and alcohol
C) Aldehyde and alcohol
D) Alcohol and amine
E) Ether and acid
3. What is the name of the ester formed from methanol and ethanoic acid?
A) Ethyl methanoate
B) Methylethanoate
C) Ethyl acetate
D) Methyl acetate
E) Methanoic acid
4. What is the typical reaction used to form esters?
A) Hydrolysis
B) Elimination
C) Esterification
D) Combustion
E) Nitration
5. What is produced during esterification along with the ester?
A) Alcohol
B) Water
C) Acid
D) Carbon dioxide
E) Hydrogen gas
6. Which functional group characterizes esters?
A) –COOH
B) –CHO
C) –OH
D) –COO–
E) –NH₂
7. What is the IUPAC name for CH₃COOCH₃?
A) Methyl acetate
B) Ethyl formate
C) Methanoic acid
D) Acetone
E) Methyl methanoate
8. What is the characteristic odor of many esters?
A) Pungent
B) Sulfur-like
C) Fruity
D) Metallic
E) Odorless
9. What is the product of the hydrolysis of an ester in acidic conditions?
A) Alcohol and carboxylic acid
B) Aldehyde and alcohol
C) Alkane and ketone
D) Alcohol and amine
E) Alcohol and ether
10. Esters can be saponified. What is the product of saponification?
A) Alcohol and ketone
B) Aldehyde and water
C) Salt of the acid and alcohol
D) Ester and water
E) Amide and acid
11. What is the main difference between esterification and hydrolysis?
A) One involves oxygen, the other does not
B) They are reverse processes
C) One requires a catalyst, the other doesn't
D) Only hydrolysis involves alcohol
E) Esterification involves amines
12. In naming esters, which part is derived from the alcohol?
A) The suffix
B) The prefix
C) The acid part
D) The root
E) The –COO–
13. Which ester is formed from ethanol and butanoic acid?
A) Butyl ethanoate
B) Ethyl butanoate
C) Ethyl ethanoate
D) Butanoic ethanoate
E) Ethanoic butanoate
14. Which of the following is NOT true about esters?
A) They are polar
B) They undergo hydrolysis
C) They are always solids at room temperature
D) They can be formed from acids and alcohols
E) They often have pleasant smells
15. Which catalyst is commonly used in esterification reactions?
A) Sodium hydroxide
B) Potassium permanganate
C) Concentrated sulfuric acid
D) Acetic acid
E) Sodium carbonate
16. What is the purpose of sulfuric acid in esterification?
A) Base catalyst
B) Dehydrating agent and acid catalyst
C) Oxidizing agent
D) Reducing agent
E) Solvent
17. What is the ester formed from phenol and benzoic acid?
A) Phenyl benzoate
B) Benzoic phenolate
C) Benzyl phenylate
D) Benzoic acid phenol ester
E) Phenylbenzene
18. What kind of bond connects the two parts of an ester molecule?
A) Ether bond
B) Ionic bond
C) Hydrogen bond
D) Covalent ester linkage
E) Van der Waals bond
19. What happens to the boiling point of esters compared to their corresponding acids?
A) It is always higher
B) It is lower due to less hydrogen bonding
C) It is the same
D) It depends only on molar mass
E) It fluctuates randomly
20. Which of the following is a common use of esters?
A) Rocket fuel
B) Artificial flavors and fragrances
C) Fertilizer
D) Glass manufacturing
E) DNA sequencing
- Questions about Ethers (Organic Chemistry)
- Questions on Aldehydes and Ketones (Organic Chemistry)
- Questions about Carboxylic Acids (Organic Chemistry)
✅ Answer Key with Extended Explanations
1. C – Esters have the structure R–COO–R', where R and R' are hydrocarbon chains.
2. B – Esters are formed by the reaction of carboxylic acids and alcohols.
3. D – Methanol + ethanoic acid → methyl acetate.
4. C – The process of forming esters is called esterification.
5. B – Esterification produces water as a byproduct.
6. D – The –COO– group is the defining feature of esters.
7. A – CH₃COOCH₃ is named methyl acetate.
8. C – Esters often smell fruity and are used in flavorings.
9. A – Acidic hydrolysis of an ester gives a carboxylic acid and an alcohol.
10. C – Saponification yields a salt of the acid (soap) and alcohol.
11. B – Hydrolysis and esterification are reverse reactions.
12. B – The prefix in the ester name comes from the alcohol.
13. B – Ethanol + butanoic acid → ethyl butanoate.
14. C – Many esters are liquids at room temperature, not always solids.
15. C – Concentrated sulfuric acid acts as the catalyst in esterification.
16. B – H₂SO₄ is both an acid catalyst and a dehydrating agent.
17. A – Phenol + benzoic acid → phenyl benzoate.
18. D – The covalent bond between –CO and –O forms the ester linkage.
19. B – Esters have lower boiling points than carboxylic acids due to less hydrogen bonding.
20. B – Esters are widely used in flavorings and fragrances due to their aromas.
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