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Acids & Alkalis

Chemistry: AQA GCSE Higher, topic 4.1.1

Acids and Alkalis

Acids and alkalis are on the opposite ends of the pH scale. They combine to form water, which is neutral.

Acids

Acids

  • Acids are substances that form hydrogen (H+) ions when they dissolve in water (aqueous solutions).
Alkalis

Alkalis

  • Alkalis are substances that form hydroxide (OH-) ions when they dissolve in water (aqueous solutions).
  • An alkali is a type of base.
Measured using pH scale

Measured using pH scale

  • The pH scale is used to measure how acidic or alkaline a substance is.

Test yourself on Acids & Alkalis

  • Which of these are true of acids?

  • Which of these are true of alkalis?

  • Which of these is true of a solution with a pH of 2?

  • Which of these is true of a solution with a pH of 9?

  • What does the pH scale measure?

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