Grade 12 Physical Sciences · Matter and Materials

Write substitution reactions and conditions

Write substitution reactions where one atom or group replaces another, and give their conditions (bromoethane + NaOH → ethanol).

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Substitution reactions Organic Chemistry ReactionsMiss Martins Maths and Science

Reactions Organic Chemistry Grade 12 | Alkane to HaloalkaneKevinmathscience

Reactions Organic Chemistry Grade 12 | Alcohol - HaloalkaneKevinmathscience

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Question 1.3 · November 2023 · 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).

1.3 Which ONE of the following is a HYDROLYSIS reaction?(2)

A $CH_{3} CH_{2} Br$ + $H_{2} O$ $\to$ $CH_{3} CH_{2} OH$ + $HBr$
B $CH_{3} CH_{2} OH$ + $HBr$ $\to$ $CH_{3} CH_{2} Br$ + $H_{2} O$
C $CH_{2} CH_{2}$ + $H_{2} O$ $\to$ $CH_{3} CH_{2} OH$
D $CH_{2} CH_{2}$ + $H_{2}$ $\to$ $CH_{3} CH_{3}$

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More past paper questions: write substitution reactions and conditions

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3. Question 4.1.5 · May/June 2023 · Paper 2 · National (DBE) · 6 marks
4.1 The flow diagram below shows different organic reactions. P, Q and R are organic compounds.

Answer the questions that follow.
For reaction 3, write down:
4.1.5 A balanced equation using STRUCTURAL FORMULAE for the organic compounds(6)
Show the memo (6 ticks)Memo
1. ✓
  Cℓ atom on second C atom of compound RReactant R: 2-chloro-2-methylpropane, with Cℓ on the second (middle) C atom.
  1 mark · Write substitution reactions and conditions
2. ✓
  Whole structure of compound R correctStructural formula of 2-chloro-2-methylpropane with all bonds and H atoms shown.
  1 mark · Draw structural formulae
3. ✓
  Inorganic reactant+ NaOH(aq) / KOH(aq) / LiOH(aq) OR $H_{2} O$
  1 mark · Write substitution reactions and conditions
4. ✓
  OH group replaces Cℓ at the same positionProduct: OH group on the second C atom, where the Cℓ was.
  1 mark · Write substitution reactions and conditions
5. ✓
  Whole structure of alcohol correctStructural formula of 2-methylpropan-2-ol with all bonds and H atoms shown.
  1 mark · Draw structural formulae
6. ✓
  Inorganic product+ NaCℓ(aq) / KCℓ(aq) / LiCℓ(aq) OR HCℓ
  (must correspond to the inorganic reactant used)
  1 mark · Write substitution reactions and conditions
4. Question 4.1.1 · November 2025 · Paper 2 · National (DBE) · 2 marks
4.1 Study the three organic reactions I, II and III below. Compounds T and W are organic compounds. R and S are inorganic substances. Consider only the major products.

Reaction I: $HBr(g) + T \to W$
Reaction II: $W + NaOH(aq) \to CH_{3} CH(OH)CH_{2} CH_{3} + R$
Reaction III: $CH_{3} CH(OH)CH_{2} CH_{3} S T + H_{2} O (ℓ)$

Write down the:
4.1.1 IUPAC name of compound W(2)
Show the memo (2 ticks)Memo
1. ✓
  Substituent: 2-bromo2-bromo
  1 mark · Write substitution reactions and conditions
2. ✓
  Stem: butanebutane
  
  Answer: 2-bromobutane
  1 mark · Write IUPAC names
5. Question 4.4.3 · November 2024 · Paper 2 · National (DBE) · 1 mark
Study the flow diagram below.

Reaction I is a CRACKING REACTION forming two organic compounds, W and T, as the ONLY products.
4.4 For reaction II, write down:
4.4.3 ONE reaction condition(1)
Show the memo (1 tick)Memo
1. ✓
  Reaction conditionUV / (sun)light / heat
  1 mark · Write substitution reactions and conditions
6. Question 4.2.4 · November 2023 · Paper 2 · National (DBE) · 1 mark
4.2 Consider the equations for reactions I to III below.

A and B represent organic compounds that are POSITIONAL ISOMERS.
X is an inorganic product.

Write down the:
4.2.4 Formula of X(1)
Show the memo (1 tick)Memo
1. ✓
  Inorganic product of hydrolysisHCl
  1 mark · Write substitution reactions and conditions

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