Hydrocarbon Derivatives – Alkanones (Ketones) and Alkanoic Acids (Carboxylic Acids)

Grade 12 · Chemistry

Semester 1 | Period 2 | Week 8

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Subject: Chemistry

Semester: 1

Period: 2

Week: 8

School Name:
Teacher’s Name:
Subject: Chemistry
Grade Level: Grade 12
Week & Period: Week 8, Period II
Date:

Topic: Hydrocarbon Derivatives – Alkanones (Ketones) and Alkanoic Acids (Carboxylic Acids)

Subtopics:

  • Alkanones: sources, nomenclature, structure, physical and chemical properties, uses.
  • Alkanoic acids: sources, classification, structure, nomenclature, physical and chemical properties, uses.

 

Learning Objectives: By the end of this lesson, learners should be able to:

  1. Identify the structural features of ketones and carboxylic acids.
  2. Classify carboxylic acids and ketones based on structure.
  3. Describe their physical and chemical properties.
  4. Name these compounds using IUPAC rules.
  5. Conduct lab tests to distinguish ketones from other functional groups.
  6. List their uses in industry and biology.

 

Previous Knowledge:
Learners have studied alcohols and aldehydes.

 

Instructional Materials:

  • Molecular model kits
  • Lab reagents for 2,4-DNP test and sodium bicarbonate test
  • Samples of propanone, butanoic acid, acetic acid
  • Functional group flashcards

 

Anticipation (Warm-Up) – 5 minutes:
Ask: “What happens when you oxidize a secondary alcohol?” Connect this with the formation of ketones.

 

Building Knowledge (Main Lesson) – 25 minutes:

  1. Alkanones (Ketones):
    • Functional group: carbonyl (C=O) between two alkyl groups.
    • Common examples: propanone, butanone.
    • Physical properties: less polar than alcohols, higher boiling point than alkanes.
    • Chemical test: 2,4-DNP test (forms orange precipitate).
    • Uses: nail polish remover (acetone), industrial solvents.
  2. Alkanoic Acids (Carboxylic Acids):
    • Functional group: –COOH.
    • Physical properties: high boiling point due to hydrogen bonding, acidic pH.
    • Chemical reactions: neutralization with bases, esterification with alcohols.
    • Sodium bicarbonate test: evolution of CO₂ confirms acid group.
    • Uses: preservatives (acetic acid), pharmaceuticals.

 

Learners’ Activities:

  • Use models to build structures of ketones and acids.
  • Conduct 2,4-DNP test on propanone.
  • React ethanoic acid with NaHCO₃ to observe CO₂ evolution.

 

Consolidation (Review and Assessment) – 10 minutes:

  • Write the structural formula of propanoic acid.
  • Give IUPAC names for given ketones.

 

Homework / Assignment:

  • Compare and contrast the physical properties of ketones and carboxylic acids.
  • Research the use of carboxylic acids in food preservation.

 

Notes – Detailed and Explained:

  • Ketones (Alkanones) are organic compounds with a carbonyl group bonded between two carbon atoms. They are formed by oxidation of secondary alcohols.
  • Carboxylic Acids (Alkanoic acids) contain the –COOH group and are weak acids. They react with metals, bases, and alcohols. Their strong hydrogen bonding gives them higher boiling points.
  • Lab tests like 2,4-DNP help detect ketones, while sodium bicarbonate test helps identify acids.

 

Expanded Notes / Instructions:

  • Emphasize safe handling of acids.
  • Include videos or animations showing acid-base reactions.
  • Relate topics to everyday products like vinegar and acetone.

 

Inclusive / Differentiation:

  • Provide visuals for functional groups.
  • Group discussions and pair work for practicals.
  • Q&A for auditory learners.

 

Teacher’s Reflection (Post-Lesson Questions):

  • Did learners understand acid reactions and ketone testing?
  • Were learners able to distinguish compounds using structure and formulae?