Grade 12 Physical Sciences · Matter and Materials

Identify functional group and series

Identify the functional group and homologous series of an organic compound (ethanol has an -OH group, so it is an alcohol).

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Types of Organic Molecules grade 12Kevinmathscience

Grade 12 Organic Chemistry Homologous series part 1Miss Martins Maths and Science

Primary, secondary or Tertiary Alcohols: Grade 12 Organic ChemistryMiss Martins Maths and Science

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Question 2.4 · May/June 2025 · Paper 2 · National (DBE) · 2 marks

The letters A to F in the table below represent organic compounds. Diagram for this question

2.4 Is compound D a PRIMARY, SECONDARY or TERTIARY alcohol? Give a reason for the answer.(2)

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More past paper questions: identify functional group and series

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3. Question 3.2 · November 2025 · Paper 2 · National (DBE) · 2 marks
Two bottles contain compounds A and B with the same molecular formula, $C_{4} H_{8} O_{2}$ . These compounds are straight chain organic molecules that belong to two different homologous series, as shown below.

The boiling points are used to distinguish between the two compounds.
3.2 Identify the TWO homologous series to which these compounds belong.(2)
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  EsterEster
  1 mark · Identify functional group and series
2. ✓
  Carboxylic acidCarboxylic acid
  1 mark · Identify functional group and series
4. Question 1.1 · May/June 2024 · Paper 2 · National (DBE) · 2 marks
1.1 The functional group for an ALDEHYDE is a ...(2)
1. A formyl group.
2. B carboxyl group.
3. C carbonyl group.
4. D hydroxyl group.
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  Choose the correct optionAldehydes have the $- CHO$ group, called the formyl group. The carbonyl group ( $C = O$ between two carbons) is the functional group of ketones; the carboxyl group belongs to carboxylic acids and the hydroxyl group to alcohols.
  
  Answer: A
  2 marks · Identify functional group and series
5. Question 4.2 · November 2024 · Paper 2 · National (DBE) · 2 marks
Study the flow diagram below.

Reaction I is a CRACKING REACTION forming two organic compounds, W and T, as the ONLY products.
4.2 Is the product in reaction II a PRIMARY, SECONDARY or TERTIARY haloalkane? Give a reason for the answer.(2)
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  PrimaryPrimary
  1 mark · Identify functional group and series
2. ✓
  ReasonThe halogen/bromine/functional group (–X) is bonded to a C atom that is bonded to one other C atom.
  1 mark · Identify functional group and series
6. Question 1.2 · November 2024 · Paper 2 · National (DBE) · 2 marks
Various options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1.11 E.
1.2 Which ONE of the following is a CORRECT GENERAL FORMULA for the carboxylic acids?(2)
1. A $C_{n} H_{2 n + 1} O_{2}$
2. B $C_{n} H_{2 n} O_{2 n}$
3. C $C_{n} H_{2 n} O_{2}$
4. D $C_{n} H_{n} O_{2}$
Show the memo (1 tick)Memo
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  Correct optionTest with ethanoic acid, $CH_{3} COOH = C_{2} H_{4} O_{2}$ : $n = 2$ gives $H_{2 n} = H_{4}$ and always 2 O atoms.
  A would give $C_{2} H_{5} O_{2}$ and B would give $C_{2} H_{4} O_{4}$ , neither of which is ethanoic acid.
  
  Answer: C
  2 marks · Identify functional group and series

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