Acids and Bases

Rucete ✏ Chemistry In a Nutshell

1. Polyprotic Acids

• Polyprotic acids can donate more than one proton (H⁺).
• Each proton is lost in a stepwise ionization.
• Each step has its own ionization constant: Ka₁ > Ka₂ > Ka₃.
• Example: Phosphoric acid (H₃PO₄) is a triprotic acid, donating three protons in three steps.

2. Oxoacids

• Oxoacids contain hydrogen, oxygen, and a central atom.
• The strength of an oxoacid depends on:
  • The number of oxygen atoms attached to the central atom.
  • The electronegativity and oxidation state of the central atom.
• More oxygens = stronger acid.
  • Example: HNO₃ (nitric acid) is stronger than HNO₂ (nitrous acid).
  • HClO₄ > HClO₃ > HClO₂ > HClO

3. Neutralization

• Acids react with bases to form salt and water.
  • Example: HNO₃ (aq) + NaOH (aq) → NaNO₃ (aq) + H₂O (l)

4. Acid-Base Properties of Ions in Aqueous Solution

Ion Type	Acidic	Basic	Neutral
Anions (–)	HSO₄⁻, H₂PO₄⁻	C₂H₃O₂⁻, CN⁻, CO₃²⁻, F⁻, HCO₃⁻, HS⁻, NO₂⁻, PO₄³⁻, S²⁻	Cl⁻, Br⁻, I⁻, ClO₄⁻, NO₃⁻, SO₄²⁻
Cations (+)	NH₄⁺, Mg²⁺, Al³⁺, transition metal ions	—	Li⁺, Na⁺, K⁺, Ca²⁺, Ba²⁺, Sr²⁺