Strong acids & Weak acids

• What pH value indicates an acid?

  A pH of less than seven
• Why do acids have a pH of less than seven?

  Because they ionize in aqueous solutions to release hydrogen ions
• What ions does hydrochloric acid dissociate into?


  H+ and Cl- ions
• What is the ionization product of nitric acid?

  A hydrogen ion and a nitrate ion
• What defines strong acids?

  They ionize completely in solution
• Name two examples of strong acids.

  Hydrochloric acid and nitric acid
• How do weak acids differ from strong acids in terms of ionization?

  Weak acids do not fully ionize in solution
• Give examples of weak acids.

  Ethanoic acid, citric acid, and carbonic acid
• What does it mean for the ionization of a weak acid to be reversible?

  There is an equilibrium between undissociated and dissociated forms
• What does the double arrow in the dissociation equation of ethanoic acid indicate?

  That the reaction is reversible
• What does it mean when we say the equilibrium lies to the left for weak acids?

  There are more undissociated acid molecules than dissociated ones
• How is acid strength different from acid concentration?

  Strength refers to how much an acid ionizes, while concentration measures the amount of acid in a volume
• Can strong acids be found in both high and low concentrations?

  Yes, strong acids can be at both high and low concentrations
• What is pH a measure of?

  The concentration of hydrogen ions in a solution
• How does the pH scale relate to hydrogen ion concentration?

  As hydrogen ion concentration increases, pH decreases
• What does a decrease of one on the pH scale represent?

  An increase in hydrogen ion concentration by a factor of 10
• If the pH changes from 5 to 3, how much does the hydrogen ion concentration increase?

  By a factor of 100
• What happens to the hydrogen ion concentration when the pH changes from 8 to 11?

  It decreases by a factor of 1,000
• How can a strong acid achieve a low pH?

  By fully dissociating to release many hydrogen ions
• What must a weak acid be to achieve a low pH?

  It must be highly concentrated
• Why does a strong acid always have a lower pH than a weak acid at the same concentration?

  Because a higher proportion of strong acid molecules dissociate to release hydrogen ions
• What ultimately determines the pH of a solution?

  The concentration of hydrogen ions