Functional Groups — Homi Bhabha Class 9 Chemistry MCQs with Solutions
Free Homi Bhabha Class 9 Chemistry Functional Groups MCQs with step-by-step solutions (12 questions). Part of Carbon & Its Compounds. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Functional Groups · medium · theory
An atom or group of atoms that gives characteristic properties to an organic compound is called a:
A. noble group
B. functional group ✓ Correct
C. periodic group
D. radical group
Solution: The functional group determines the chemical behaviour of an organic compound.
Q2 — Functional Groups · medium · theory
The functional group present in alcohols (such as ethanol) is:
A. –CO– (ketone)
B. –COOH (carboxyl)
C. –CHO (aldehyde)
D. –OH (hydroxyl) ✓ Correct
Solution: Alcohols contain the hydroxyl group, –OH.
Q3 — Functional Groups · hard · theory
The functional group present in carboxylic acids like acetic acid is:
A. –OH (hydroxyl)
B. –NH₂ (amine)
C. –CHO (aldehyde)
D. –COOH (carboxyl) ✓ Correct
Solution: Carboxylic acids contain the carboxyl group, –COOH.
Q4 — Functional Groups · medium · theory
Ethanol (an alcohol) is commonly used:
A. in alcoholic drinks and as a sanitiser ✓ Correct
B. as a fertiliser
C. to make cement
D. as a fuel gas for cooking
Solution: Ethanol is used in beverages, sanitisers and as a solvent/fuel additive.
Q5 — Functional Groups · medium · theory
Vinegar, used in cooking, is a dilute solution of:
A. sulphuric acid
B. hydrochloric acid
C. sodium hydroxide
D. acetic acid (ethanoic acid) ✓ Correct
Solution: Vinegar is about 5–8% acetic (ethanoic) acid in water.
Q6 — Functional Groups · hard · theory
The compound ethanoic acid contains which functional group?
A. hydroxyl (–OH)
B. ketone (>C=O)
C. aldehyde (–CHO)
D. carboxyl (–COOH) ✓ Correct
Solution: Ethanoic acid (acetic acid) has the carboxyl group, –COOH.
Q7 — Functional Groups · hard · theory
The functional group –CHO is characteristic of:
A. alcohols
B. aldehydes ✓ Correct
C. ketones
D. carboxylic acids
Solution: The –CHO group is the aldehyde functional group.
Q8 — Functional Groups · easy · theory
Which functional group is present in alcohols?
A. -CHO (aldehyde)
B. -COOH (carboxyl)
C. -OH (hydroxyl) ✓ Correct
D. >C=O (carbonyl)
Solution: Alcohols are characterised by the hydroxyl group, -OH, as in ethanol (C2H5OH). The other groups define acids, aldehydes and ketones.
Q9 — Functional Groups · easy · theory
Vinegar owes its sourness to acetic acid. Which functional group does acetic acid contain?
A. >C=O (ketone)
B. -COOH (carboxyl) ✓ Correct
C. -OH (hydroxyl)
D. -CHO (aldehyde)
Solution: Acetic acid (ethanoic acid, CH3COOH) contains the carboxyl group -COOH, which is responsible for its acidic, sour nature.
Q10 — Functional Groups · medium · theory
Which of the following correctly matches a compound with its functional group?
A. CH3CHO -> aldehyde ✓ Correct
B. CH3COOH -> alcohol
C. CH3OH -> carboxylic acid
D. CH3COCH3 -> aldehyde
Solution: CH3CHO ends in -CHO, the aldehyde group, so this match is correct. CH3OH is an alcohol, CH3COOH is a carboxylic acid, and CH3COCH3 (acetone) is a ketone, so the other three are wrongly matched.
Q11 — Functional Groups · hard · theory
Assertion (A): Ethanoic acid turns blue litmus red. Reason (R): It contains the carboxyl (-COOH) group, which makes it behave as an acid. Choose the correct option.
A. Both A and R are true, and R correctly explains A ✓ Correct
B. A is true but R is false
C. Both A and R are true, but R does not explain A
D. A is false but R is true
Solution: Ethanoic acid is acidic and does turn blue litmus red (A is true). This acidity arises from the carboxyl group -COOH (R is true), and that group is exactly why it is acidic, so R correctly explains A.
Q12 — Functional Groups · hard · theory
The molecular formula C2H6O can represent two different compounds (isomers) that have different functional groups. Which pair are they?
A. Methanol and methanal
B. Ethanoic acid and ethanol
C. Ethene and ethyne
D. Ethanol (-OH group) and dimethyl ether (-O- linkage) ✓ Correct
Solution: Both ethanol (CH3CH2OH) and dimethyl ether (CH3OCH3) have the formula C2H6O but different functional groups (a hydroxyl versus an ether linkage), making them functional isomers. The other pairs have different molecular formulas.