concepts
Acids vs Bases
Acids vs Bases
Fundamental categories of chemical substances with opposite properties. Acids donate protons (Bronsted-Lowry) or accept electrons (Lewis). Bases accept protons or donate electrons.
Comparison Table
| Feature | Acids | Bases |
|---|---|---|
| Bronsted-Lowry Definition | Proton (H+) donor | Proton (H+) acceptor |
| Lewis Definition | Electron pair acceptor | Electron pair donor |
| pH Range | < 7 | > 7 |
| Taste | Sour | Bitter |
| Litmus Paper | Turns blue litmus red | Turns red litmus blue |
| In Water | Produces H3O+ ions | Produces OH- ions |
| Reaction Together | Neutralization produces water + salt | Neutralization produces water + salt |
| Examples | HCl, H2SO4, CH3COOH | NaOH, NH3, NaHCO3 |
Key Differences
- →Acids have pH < 7; bases have pH > 7
- →Acids increase [H+] in solution; bases increase [OH-]
- →Conjugate acid-base pairs differ by one proton
- →Strong acids/bases dissociate completely; weak ones partially dissociate
- →The stronger the acid, the weaker its conjugate base (and vice versa)
When to Use Acids
- ✓Lowering pH of a solution
- ✓Dissolving metals (reactive metals + acid produce H2)
- ✓Neutralizing bases
- ✓Catalyzing reactions requiring proton transfer
When to Use Bases
- ✓Raising pH of a solution
- ✓Neutralizing acids
- ✓Saponification (making soap)
- ✓Catalyzing reactions requiring nucleophilic attack
Common Confusions
- !Thinking all acids are strong (most are weak)
- !Confusing pH with acid strength (concentration matters)
- !Forgetting that water is amphoteric (can act as acid or base)
- !Not distinguishing between Bronsted-Lowry and Lewis definitions
FAQs
Common questions about this comparison
Strong acids dissociate completely in water (HCl, HNO3, H2SO4). Weak acids only partially dissociate and exist in equilibrium with their conjugate base (CH3COOH, HF). Ka values indicate acid strength.
Neutralization occurs: acid + base produces water + salt. For example, HCl + NaOH produces H2O + NaCl. The pH of the resulting solution depends on the relative strengths of the acid and base.