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Ka and Kb of compounds quiz

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  • What does the equilibrium constant Ka represent?
    Ka represents the acid dissociation constant for a weak acid and measures the strength of weak acids.
  • What does the equilibrium constant Kb represent?
    Kb represents the base dissociation constant for a weak base and measures the strength of weak bases.
  • How are Ka and acid strength related?
    A higher Ka value indicates a stronger acid, which produces more H+ ions in solution.
  • What is the typical value range for Ka and Kb of weak acids and bases?
    Both Ka and Kb for weak acids and bases are less than 1.
  • What does a Ka or Kb value less than 1 indicate about product formation?
    It indicates that very little product is formed and the reaction establishes an equilibrium.
  • What is the relationship between Ka, Kb, and Kw?
    Ka and Kb are related by the equation Kw = Ka × Kb, where Kw is the ion product constant for water.
  • What is the value of Kw at 25°C?
    At 25°C, Kw equals 1.0 × 10⁻¹⁴.
  • How can you find Kb if you know Ka for a conjugate acid-base pair?
    You can find Kb by dividing Kw by Ka: Kb = Kw / Ka.
  • What is ignored in the equilibrium expression for Ka and Kb?
    Solids and liquids, such as water, are ignored in the equilibrium expression.
  • What is the general form of the equilibrium expression for Ka?
    Ka = [A⁻][H₃O⁺] / [HA], where water is not included in the expression.
  • What is the general form of the equilibrium expression for Kb?
    Kb = [BH⁺][OH⁻] / [B], ignoring water in the expression.
  • According to the Bronsted-Lowry theory, what does a weak acid do in water?
    A weak acid donates an H⁺ to water, forming A⁻ and H₃O⁺.
  • According to the Bronsted-Lowry theory, what does a weak base do in water?
    A weak base accepts an H⁺ from water, forming BH⁺ and OH⁻.
  • How are pKa and Ka related?
    A higher Ka corresponds to a lower pKa, indicating a stronger acid.
  • Why do weak acids and bases establish equilibrium in solution?
    Because they only partially ionize, resulting in both reactants and products being present at equilibrium.