Organic Chemistry Practice Questions
NECO (Nigeria) · NECO Chemistry · 142 free MCQs with instant results and detailed explanations.
142
Total
39
Easy
73
Medium
30
Hard
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Sample Questions from Organic Chemistry
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
Which of the following is a property of alkanes?
A.
They are highly reactive.
B.
They contain only single bonds.
C.
They have functional groups.
D.
They are soluble in water.
Show Answer & Explanation
Correct Answer: B
Alkanes are saturated hydrocarbons that contain only single bonds between carbon atoms, making option B correct. Other options incorrectly describe alkanes as reactive, having functional groups, or being water-soluble.
Q2
Easy
Which reaction involves the addition of hydrogen to an alkene?
A.
Dehydration
B.
Hydrogenation
C.
Polymerization
D.
Halogenation
Show Answer & Explanation
Correct Answer: B
Hydrogenation is the process where hydrogen is added to an alkene, converting it to an alkane. The other options refer to different types of reactions that do not involve the addition of hydrogen.
Q3
Easy
Which of the following compounds is an example of a carboxylic acid?
A.
Ethanol
B.
Acetic acid
C.
Benzene
D.
Butane
Show Answer & Explanation
Correct Answer: B
Acetic acid (CH3COOH) is a carboxylic acid because it contains a carboxyl group (-COOH). Ethanol, benzene, and butane do not have the carboxyl functional group, making option B the correct answer.
Q4
Medium
Which of the following compounds is an example of a primary alcohol?
A.
1-butanol
B.
2-butanol
C.
Cyclohexanol
D.
Butanol
Show Answer & Explanation
Correct Answer: A
1-butanol has the hydroxyl group (-OH) attached to a terminal carbon, making it a primary alcohol. In contrast, 2-butanol has the -OH on a second carbon, classifying it as a secondary alcohol.
Q5
Medium
What is the major product when propene reacts with bromine in an aqueous solution?
A.
1-bromopropane
B.
2-bromopropanol
C.
Bromopropane
D.
1,2-dibromopropane
Show Answer & Explanation
Correct Answer: B
The reaction of propene with bromine in an aqueous medium leads to bromohydrin formation, particularly 2-bromopropanol, due to the nucleophilic attack of water on the bromonium ion intermediate.
Q6
Medium
Which functional group characterizes carboxylic acids?
A.
Aldehyde group
B.
Amine group
C.
Carboxyl group
D.
Hydroxyl group
Show Answer & Explanation
Correct Answer: C
Carboxylic acids are characterized by the carboxyl group (-COOH), which consists of a carbonyl (C=O) and a hydroxyl (-OH) group attached to the same carbon.
Q7
Medium
What type of reaction occurs when an alkene is converted into an alkane?
A.
Hydrolysis
B.
Hydrogenation
C.
Dehydration
D.
Halogenation
Show Answer & Explanation
Correct Answer: B
The conversion of an alkene to an alkane involves the addition of hydrogen across the double bond, a process known as hydrogenation, typically using a catalyst.
Q8
Hard
Which of the following compounds is a primary alcohol?
A.
Butan-1-ol
B.
Butan-2-ol
C.
2-Methylpropan-2-ol
D.
Cyclohexanol
Show Answer & Explanation
Correct Answer: A
Butan-1-ol is a primary alcohol because the hydroxyl (-OH) group is attached to the first carbon of the butane chain, making it a straight-chain alcohol. Primary alcohols have the -OH group on a terminal carbon.
Q9
Hard
What is the major product of the reaction between ethene and bromine in the presence of a liquid solvent?
A.
Ethane
B.
1,2-Dibromoethane
C.
Bromoethane
D.
Vinyl bromide
Show Answer & Explanation
Correct Answer: B
The reaction of ethene with bromine (an electrophilic addition reaction) in a liquid solvent results in the formation of 1,2-dibromoethane. This product is formed because bromine adds across the double bond of ethene, leading to a vicinal dibromide.
Q10
Hard
What is the IUPAC name for the compound with the molecular formula C5H10O, which has a carbonyl group at the second carbon and a methyl group at the third carbon?
A.
3-methylpentan-2-one
B.
2-pentanone
C.
4-methyl-2-pentanone
D.
2-methylbutan-3-one
Show Answer & Explanation
Correct Answer: A
The correct name is 3-methylpentan-2-one, as the longest carbon chain is five carbons with a methyl branch at the third carbon and a ketone at the second carbon.
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Organic Chemistry — NECO (Nigeria) NECO Chemistry Practice Questions Online
This page contains 142 practice MCQs for the chapter Organic Chemistry in NECO (Nigeria) NECO Chemistry. The questions are organized by difficulty — 39 easy, 73 medium, 30 hard — so you can choose the right level for your preparation.
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