The Lewis theory of acids and bases gives us a wider view compared to traditional definitions. In this theory:

• Lewis acids are substances that accept electron pairs.
• Lewis bases are substances that donate electron pairs.

This change in focus helps us understand acid-base reactions better, especially in areas like organic and coordination chemistry.

Key Differences

1. Electron Acceptance vs. Donation:

   • Lewis Acids: These are substances that can take in a pair of electrons to create a bond. A good example is aluminum chloride (AlCl₃). It can accept an electron pair from a Lewis base to fill its outer shell of electrons.
   • Lewis Bases: On the other hand, Lewis bases are substances that can give away a pair of electrons. A common example is ammonia (NH₃), which has extra electrons on its nitrogen atom that it can donate to a Lewis acid.

2. Types of Reactions:

   • In a Lewis acid-base reaction, the Lewis base donates its electron pair to the Lewis acid. This forms a special bond called a coordinate covalent bond. This is different from the Brønsted-Lowry theory, which talks about the transfer of protons (hydrogen ions).
   • For example, when ammonia (NH₃) reacts with boron trifluoride (BF₃), ammonia acts as a Lewis base, and boron trifluoride acts as a Lewis acid. The reaction looks like this: $\text{BF}_3 + \text{NH}_3 \rightarrow \text{F}_3\text{B-NH}_3$

3. Broader Use:

   • The Lewis theory includes reactions that may not fit the old definitions of acids and bases. For example, metal ions like Fe³⁺ can act as Lewis acids by accepting electron pairs from other substances called ligands in coordination compounds.

Summary

To sum up, the Lewis theory helps us understand acid-base interactions by focusing on electron pairs instead of just protons. This way, we can notice different substances as acids or bases based on whether they donate or accept electrons.

By understanding the roles of Lewis acids and bases in electron transfer, we can explore the world of chemical reactions better. This knowledge is especially useful when studying organic reactions or looking at coordination chemistry in Grade 12!