How does substituent position affect reactivity?

• Ortho = next to the substituent
• Meta = one carbon away
• Para = opposite side

How it affects reactivity:

1. Activating groups (like –OH, –NH₂)
   • Make the ring more reactive
   • New groups usually attach at ortho and para positions
2. Deactivating groups (like –NO₂, –COOH)
   • Make the ring less reactive
   • New groups usually attach at meta position
3. Big groups can block ortho positions, so para is easier to react.

Simple rule:

• Electron-donating → ortho/para
• Electron-withdrawing → meta