11

• What is one way to identify if a solution is acidic or basic?

  Litmus paper
• What is another method to identify if a solution is acidic or basic?

  Indicator and colour scale
• What is a third way to identify if a solution is acidic or basic?

  pH meter
• How does red litmus paper indicate an alkali?

  It turns blue
• What happens to blue litmus paper in an alkali?

  It remains blue
• How does blue litmus paper indicate an acid?

  It turns red
• What happens to red litmus paper in an acid?

  It remains red
• Why might a pH meter be preferred over universal indicator?

  It gives a numerical value for pH
• What is the accuracy of a pH meter typically measured to?

  Two decimal places
• What does the term 'accuracy' refer to?

  How close the measurement is to true value
• What is the equation linking pH and hydrogen ion concentration?

  pH = -log[H+]
• What is the alternative equation for hydrogen ion concentration from pH?

  [H+] = 10^-pH
• What are the steps to carry out a titration?

  1. Measure first solution into conical flask using a pipette.
  2. Add a few drops of a suitable indicator.
  3. Fill burette with the other solution and record initial volume.
  4. Slowly add solution from burette to conical flask.
  5. Swirl mixture continuously until end point is reached.
  6. Repeat until concordant results are obtained.
• What colour does methyl orange turn in an acid?

  Red
• What colour does methyl orange turn in an alkali?

  Yellow
• What colour is methyl orange in a neutral solution?

  Orange
• What colour is phenolphthalein in an acid?

  Colourless
• What colour is phenolphthalein in an alkali?

  Pink
• What is a Brønsted-Lowry acid?

  A substance that donates protons (H+)
• What is a Brønsted-Lowry base?

  A substance that accepts protons (H+)
• What is the difference between a strong and weak acid?

  Strong acid completely dissociates in solution
• What characterizes a solution with a pH of 1.00?

  It is acidic and likely contains a strong acid