pH Scale and Strong Acids

pH Scale

• The pH scale measures the concentration of hydrogen ions (H+) in a solution
• pH = -log[H+]
• pH ranges from 0 to 14, with:
  • pH 7: neutral (equimolar concentrations of H+ and OH-)
  • pH < 7: acidic (excess H+)
  • pH > 7: basic (excess OH-)

Strong Acids

• Completely dissociate in water to produce H+ and an anion
• Examples:
  1. Hydrochloric acid (HCl)
  2. Sulfuric acid (H2SO4)
  3. Nitric acid (HNO3)
  4. Perchloric acid (HClO4)
• Characteristics:
  • High dissociation constant (Ka)
  • Completely ionize in water
  • Produce a high concentration of H+ ions

Weak Acids

• Partially dissociate in water to produce H+ and an anion
• Examples:
  1. Acetic acid (CH3COOH)
  2. Carbonic acid (H2CO3)
  3. Citric acid (C6H8O7)
  4. Formic acid (HCOOH)
• Characteristics:
  • Low dissociation constant (Ka)
  • Partially ionize in water
  • Produce a low concentration of H+ ions

pH Scale

• Measures the concentration of hydrogen ions (H+) in a solution
• Calculated using the formula pH = -log[H+]
• Ranges from 0 to 14
• Neutral pH: 7, where H+ and OH- concentrations are equimolar
• Acidic pH: < 7, with excess H+ ions
• Basic pH: > 7, with excess OH- ions

Strong Acids

• Completely dissociate in water to produce H+ and an anion
• Characteristics:
• High dissociation constant (Ka)
• Complete ionization in water
• Produce high concentrations of H+ ions
• Examples:
• Hydrochloric acid (HCl)
• Sulfuric acid (H2SO4)
• Nitric acid (HNO3)
• Perchloric acid (HClO4)

Weak Acids

• Partially dissociate in water to produce H+ and an anion
• Characteristics:
• Low dissociation constant (Ka)
• Partial ionization in water
• Produce low concentrations of H+ ions
• Examples:
• Acetic acid (CH3COOH)
• Carbonic acid (H2CO3)
• Citric acid (C6H8O7)
• Formic acid (HCOOH)