Calculating the pH of Strong Monobasic Acids

• What is a characteristic of a monobasic acid?

  A monobasic acid donates ONE H⁺ ion per molecule of acid.
• What does it mean for a strong acid to dissociate completely?

  It means that the acid breaks down entirely into its ions in solution.
• Give two examples of strong monobasic acids.

  HCl (hydrochloric acid) and HNO₃ (nitric acid).
• How do you calculate the pH of strong monobasic acids?

  • Use the formula: $\text{pH} =$$-\log[H^+]$
  • [H⁺] is the concentration of the acid in moldm⁻³.
• What happens to the pH as the concentration of a strong monobasic acid increases?

  The higher the concentration, the lower the pH.
• What is the formula to calculate pH from hydrogen ion concentration?

  pH = -log[H⁺]
• What is the pH of a 0.500 moldm⁻³ HCl solution?

  The pH is 0.3.
• Calculate the pH of the following strong monobasic acid solutions (to 1 d.p.):

  1. 0.600 moldm⁻³ HCl
  2. 0.800 moldm⁻³ HNO₃
  3. 0.440 moldm⁻³ HClO₄
  4. pH = -log(0.600) ≈ 0.2
  5. pH = -log(0.800) ≈ 0.1
  6. pH = -log(0.440) ≈ 0.4
• What is the significance of the button on your calculator mentioned in the study material?

  It is used to find the logarithm of the hydrogen ion concentration.