Chem 120: OrganiC Chemistry – FunCtiOnal grOups||QuestiOns
and answers with ratiOnales/graded a+/2026 update/100%
COrreCt /instant dOwnlOad
**1. Which functional group is characterized by a carbon–oxygen double bond (C=O)?**
A) Hydroxyl
B) Carbonyl
C) Ether
D) Amine
**Answer:** B) Carbonyl
**Rationale:** The carbonyl group (C=O) is found in aldehydes, ketones, carboxylic acids,
esters, and amides. Hydroxyl is –OH, ether is C–O–C, and amine contains nitrogen.
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**2. Which of the following contains a hydroxyl group (–OH)?**
A) Ethanal
B) Acetone
C) Ethanol
D) Diethyl ether
**Answer:** C) Ethanol
**Rationale:** Ethanol (CH₃CH₂OH) has an –OH group. Ethanal has an aldehyde (CHO), acetone
is a ketone (C=O), and diethyl ether has C–O–C.
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**3. What is the functional group in a carboxylic acid?**
, A) –OH
B) –CHO
C) –COOH
D) –COOR
**Answer:** C) –COOH
**Rationale:** –COOH is the carboxyl group (carbonyl + hydroxyl). –CHO is aldehyde, –COOR is
ester.
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**4. The general formula R–O–R' represents which functional group?**
A) Ester
B) Ether
C) Alcohol
D) Aldehyde
**Answer:** B) Ether
**Rationale:** Ethers have an oxygen single-bonded to two alkyl or aryl groups. Esters are R–
COO–R', alcohols are R–OH, aldehydes are R–CHO.
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**5. Which functional group is found in methylamine (CH₃NH₂)?**
A) Amide
B) Primary amine
C) Secondary amine
D) Nitrile
**Answer:** B) Primary amine
and answers with ratiOnales/graded a+/2026 update/100%
COrreCt /instant dOwnlOad
**1. Which functional group is characterized by a carbon–oxygen double bond (C=O)?**
A) Hydroxyl
B) Carbonyl
C) Ether
D) Amine
**Answer:** B) Carbonyl
**Rationale:** The carbonyl group (C=O) is found in aldehydes, ketones, carboxylic acids,
esters, and amides. Hydroxyl is –OH, ether is C–O–C, and amine contains nitrogen.
---
**2. Which of the following contains a hydroxyl group (–OH)?**
A) Ethanal
B) Acetone
C) Ethanol
D) Diethyl ether
**Answer:** C) Ethanol
**Rationale:** Ethanol (CH₃CH₂OH) has an –OH group. Ethanal has an aldehyde (CHO), acetone
is a ketone (C=O), and diethyl ether has C–O–C.
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**3. What is the functional group in a carboxylic acid?**
, A) –OH
B) –CHO
C) –COOH
D) –COOR
**Answer:** C) –COOH
**Rationale:** –COOH is the carboxyl group (carbonyl + hydroxyl). –CHO is aldehyde, –COOR is
ester.
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**4. The general formula R–O–R' represents which functional group?**
A) Ester
B) Ether
C) Alcohol
D) Aldehyde
**Answer:** B) Ether
**Rationale:** Ethers have an oxygen single-bonded to two alkyl or aryl groups. Esters are R–
COO–R', alcohols are R–OH, aldehydes are R–CHO.
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**5. Which functional group is found in methylamine (CH₃NH₂)?**
A) Amide
B) Primary amine
C) Secondary amine
D) Nitrile
**Answer:** B) Primary amine
