PH Scale

• What is the main focus of the video discussed in the study material?

  The difference between strong and weak acids and their relation to pH
• What pH value indicates an acid?

  A pH of less than seven
• Why do acids form aqueous solutions with 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 does nitric acid ionize into?

  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 the double arrow in the dissociation equation of ethanoic acid indicate?

  That the reaction is reversible
• What does it mean that the ionization of a weak acid is reversible?

  There is an equilibrium between undissociated and dissociated forms of the acid
• 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 at equilibrium
• How should one not confuse acid strength with 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 hydrogen ion concentration when 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 and releasing many hydrogen ions
• What must a weak acid do to achieve a low pH?

  It must be highly concentrated to release enough hydrogen ions
• At any given concentration, how does the pH of a strong acid compare to that of a weak acid?

  A strong acid will always have a lower pH than a weak acid
• What determines the pH of a solution?

  The concentration of hydrogen ions