Lewis Acids and Bases: Definition, Examples, and Electron Flow

📚 Quick Study Guide

• ⚛️ Lewis acids are electron-pair acceptors. Think of them as electron 'hogs'!
• ⚖️ Lewis bases are electron-pair donors. They're generous with their electrons.
• ➡️ Electron flow is shown with curved arrows, always going from the base (electron source) to the acid (electron sink).
• 🤝 A Lewis acid-base adduct is formed when a Lewis acid and base combine.
• 🧪 Examples of Lewis acids: $BF_3$, $AlCl_3$, $FeCl_3$
• 💡 Examples of Lewis bases: $NH_3$, $H_2O$, $Cl^-$
• 📝 Key difference from Bronsted-Lowry: Lewis definition doesn't require $H^+$ transfer.

Practice Quiz

1. Which of the following is a Lewis acid?
   1. $NH_3$
   2. $H_2O$
   3. $BF_3$
   4. $OH^-$
2. Which of the following is a Lewis base?
   1. $AlCl_3$
   2. $H^+$
   3. $CH_4$
   4. $CN^-$
3. In the reaction between $NH_3$ and $BF_3$, which molecule acts as the Lewis base?
   1. $BF_3$
   2. $NH_3$
   3. Neither
   4. Both
4. What is the key characteristic of a Lewis acid?
   1. It donates a proton.
   2. It accepts a proton.
   3. It donates an electron pair.
   4. It accepts an electron pair.
5. Which of the following species can act as both a Lewis acid and a Lewis base?
   1. $H_2O$
   2. $BF_3$
   3. $NH_4^+$
   4. $Cl^-$
6. Which of the following reactions is a Lewis acid-base reaction?
   1. $HCl + NaOH \rightarrow NaCl + H_2O$
   2. $Ag^+ + 2NH_3 \rightarrow [Ag(NH_3)_2]^+$
   3. $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$
   4. $NaCl \rightarrow Na^+ + Cl^-$
7. What does the curved arrow represent in a Lewis acid-base reaction mechanism?
   1. Movement of protons
   2. Movement of neutrons
   3. Movement of electron pairs
   4. Movement of atoms