Concise Notes on Acids, Bases, and pH

Acids and Bases

Acids

  • Common acids include hydrochloric acid HClHCl, sulfuric acid H<em>2SO</em>4H<em>2SO</em>4, and phosphoric acid H<em>3PO</em>4H<em>3PO</em>4.
  • Monoprotic acids donate one proton (e.g., HClHCl), diprotic acids donate two (e.g., H<em>2SO</em>4H<em>2SO</em>4), and triprotic acids donate three (e.g., H<em>3PO</em>4H<em>3PO</em>4).
  • Acidic solutions form when non-metal oxides react with water.

Bases

  • Common bases include sodium hydroxide NaOHNaOH, calcium hydroxide Ca(OH)<em>2Ca(OH)<em>2, and aluminum hydroxide Al(OH)</em>3Al(OH)</em>3.
  • Bases dissociate in water to form hydroxide ions (OH−)(OH^-).
  • Alkaline solutions form when metal oxides react with water.

Dissociation of Acids

  • Monoprotic acids: HCl+H<em>2O→H</em>3O++Cl−HCl + H<em>2O \rightarrow H</em>3O^+ + Cl^-
  • Diprotic acids:
    • H<em>2SO</em>4+H<em>2O→H</em>3O++HSO4−H<em>2SO</em>4 + H<em>2O \rightarrow H</em>3O^+ + HSO_4^-
    • HSO<em>4−+H</em>2O→H<em>3O++SO</em>42−HSO<em>4^- + H</em>2O \rightarrow H<em>3O^+ + SO</em>4^{2-}
  • Triprotic acids (e.g., H<em>3PO</em>4H<em>3PO</em>4) dissociate in three steps.

Dissociation of Water

  • H<em>2O+H</em>2O⇌H3O++OH−H<em>2O + H</em>2O \rightleftharpoons H_3O^+ + OH^-
  • Ion product of water: [H3O+][OH−]=1⋅10−7mol/L[H_3O^+][OH^-] = 1 \cdot 10^{-7} mol/L

pH

  • Definition: pH=−log[H3O+]pH = -log[H_3O^+]
  • pH+pOH=14pH + pOH = 14

Neutralization

  • Acid + Base → Salt + Water (e.g., HCl+NaOH→NaCl+H2OHCl + NaOH \rightarrow NaCl + H_2O)

Formation of Acidic and Alkaline Solutions

  • Non-metals + Oxygen → Non-metal oxides + H2OH_2O → Acidic solution
  • Metals + Oxygen → Metal oxides + H2OH_2O → Alkaline solution

Hydrogen Bonding

  • Hydrogen bonds (Wasserstoffbrückenbindung) are intermolecular forces responsible for water being a liquid at room temperature.

Polarity

  • Polar molecules have uneven charge distribution (dipole moment).
  • Non-polar molecules have even charge distribution.

Titration

  • Titration (volumetric analysis) is a method to determine the concentration of an acid or base.
  • Formula: c<em>1⋅V</em>1=c<em>2⋅V</em>2c<em>1 \cdot V</em>1 = c<em>2 \cdot V</em>2

Ampholyte

  • Water can react as an acid or a base.

Experiment Results

  • Metals + Oxygen -> Metal Oxides + H2OH_2O -> Alkaline Solution
  • Non-Metals + Oxygen -> Non-Metal Oxides + H2OH_2O -> Acidic Solution