Organic Chemistry Practice Questions
WAEC (West Africa) · WAEC Chemistry · 137 free MCQs with instant results and detailed explanations.
137
Total
42
Easy
65
Medium
30
Hard
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Sample Questions from Organic Chemistry
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Q1
Easy
Which of the following compounds is an example of an alcohol?
A.
C2H5OH
B.
C3H6
C.
C4H10
D.
C6H12O6
Show Answer & Explanation
Correct Answer: A
C2H5OH, also known as ethanol, is a simple alcohol. It contains a hydroxyl (-OH) group, which is characteristic of alcohols, distinguishing it from the other options.
Q2
Easy
Which reaction type is involved in converting an alkene to an alkane?
A.
Hydrogenation
B.
Halogenation
C.
Dehydration
D.
Oxidation
Show Answer & Explanation
Correct Answer: A
Hydrogenation is the reaction that involves the addition of hydrogen to an alkene, converting it into an alkane by saturating the double bond with hydrogen atoms.
Q3
Easy
Which of the following compounds is an example of an alkane?
A.
C2H6
B.
C2H4
C.
C3H8
D.
C4H10O
Show Answer & Explanation
Correct Answer: A
C2H6 is ethane, which is an alkane. Alkanes are saturated hydrocarbons with only single bonds between carbon atoms.
Q4
Medium
Which of the following compounds is an example of an alkene?
A.
C2H4
B.
C2H6
C.
C3H8
D.
C4H10
Show Answer & Explanation
Correct Answer: A
C2H4 is an alkene because it contains a carbon-carbon double bond, which is characteristic of alkenes. The other options are alkanes with only single bonds.
Q5
Medium
What is the functional group present in carboxylic acids?
A.
-OCH3
B.
-COOH
C.
-NH2
D.
-OH
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Correct Answer: B
The functional group -COOH defines carboxylic acids, making it distinct from other organic compounds like alcohols (-OH) and amines (-NH2).
Q6
Medium
Which of the following reactions is an example of an elimination reaction?
A.
But-1-ene + H2 → Butane
B.
Ethyl bromide + KOH → Ethylene + KBr + H2O
C.
Propane + Cl2 → Propyl chloride + HCl
D.
Hexane + O2 → Carbon dioxide + Water
Show Answer & Explanation
Correct Answer: B
In the reaction Ethyl bromide + KOH, a molecule of HBr is eliminated to form ethylene, which is characteristic of elimination reactions.
Q7
Medium
Which of the following statements about isomers is false?
A.
Isomers have the same molecular formula.
B.
Isomers have different physical and chemical properties.
C.
Isomers always have the same structural arrangement.
D.
Isomers can differ in the arrangement of atoms.
Show Answer & Explanation
Correct Answer: C
Isomers, by definition, have the same molecular formula but can differ in their structural arrangement, making statement C false.
Q8
Hard
Which of the following compounds will undergo hydrolysis most readily in an aqueous solution?
A.
Chloroethane
B.
Bromoethane
C.
Iodoethane
D.
Fluoroethane
Show Answer & Explanation
Correct Answer: C
Iodoethane hydrolyzes more readily because the C-I bond is the weakest among the halogenated alkanes, allowing it to break more easily in the presence of water.
Q9
Hard
A compound has the formula C5H10O. Which of the following could be its structure if it is known to be a ketone?
A.
2-Pentanone
B.
3-Pentanone
C.
Cyclopentanone
D.
Pentanal
Show Answer & Explanation
Correct Answer: B
3-Pentanone is a ketone with the structure of C5H10O, where the carbonyl group is located at the third carbon, making it a valid ketone structure.
Q10
Hard
Which of the following compounds is the most likely product of the reaction between propan-1-ol and concentrated sulfuric acid at elevated temperatures?
A.
Propene
B.
Propanal
C.
Propan-2-ol
D.
2-Methylpropan-2-ol
Show Answer & Explanation
Correct Answer: A
The reaction between propan-1-ol and concentrated sulfuric acid leads to dehydration, primarily resulting in the formation of propene. Other options do not accurately represent the expected dehydration product under these conditions.
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Organic Chemistry — WAEC (West Africa) WAEC Chemistry Practice Questions Online
This page contains 137 practice MCQs for the chapter Organic Chemistry in WAEC (West Africa) WAEC Chemistry. The questions are organized by difficulty — 42 easy, 65 medium, 30 hard — so you can choose the right level for your preparation.
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