🎈 Concept: Substitution reactions = Replacing an atom/group in a molecule with another atom/group.

• Alkanes = Non-reactive. Why?
  • Strong C-C (346kJmol–1) & C-H (414kJmol–1) bonds.
  • Bonds = Non-polar. (Think: Opposites attract, but like-minded folks? Meh. 🤷)
• To make them less "shy", we can introduce them to a polar bond! 💃

• Halogenate alkanes to make them reactive.
• E.g., methane + chlorine + UV light/heat = chloromethane + hydrogen chloride.

• Initiation

  • What? Molecule breaks to produce radical species.
  • Real-world example: Think of splitting a chocolate bar in two. Each piece (radical) is hungry for more!
  • Fun Fact: Under UV light, chlorine splits to create 2 identical chlorine radicals, Cl•. It's twins!

• Propagation

  • What? A radical reacts with a non-radical, creating a new radical.
  • Real-world example: A friend introduces you to another friend, but then leaves you two alone. Awkward! You (radical) introduce your new friend (non-radical) to another one of your friends (new radical). The cycle continues.
  • Fun Fact: This is a chain reaction. It's like the famous game "Telephone"!

• Termination

  • What? Two radicals meet and form a non-radical.
  • Real-world example: Two friends finally meet and start a new project together, not needing to introduce anyone else. They're content!
  • Fun Fact: This slows down the reaction. Think of it as ending the "Telephone" game.