Acid-base equilibria

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The equilibrium law helps to make sense of the behaviour of acids and bases. The theory helps to account for the behaviour of strong and weak acids as well as explaining the the way that indicators and buffer solutions work.

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Tutorials

• Sorted FAQs on Acid-Base equilibria
• Ionisation constants for acids: audio tutorial
• Is calcium hydroxide a strong or a weak base?

Webguides

• Indicator colour changes
• The pH of solutions of sulphuric acid
• Key ideas about acid-base equilibria

Recently Asked Questions

• I'm struggling to get my head around buffers. I understand the basic principles of buffers but I don't understand how to work out how the two equilibriums work together. For example, one exam question is: "Mixtures of ammonia, NH₃ and ammonium chloride, NH₄Cl, can be used as a basis of buffer solutions. Explain how this mixture acts as a buffer solution." The two equilibria are: NH₄⁺ --> NH₃ + H⁺ NH₃ + H₂O --> NH₄⁺ + OH^- Please can you explain how adding acid and alkali effects the equilibrium and why. 060608
• Why it is important that the same number of drops of methyl orange is used in each titration? 020608
• I'm doing an investigation on choosing a suitable indicator for a strong acid (hydrochloric acid) and a weak base (ammonia) titration. The options are methyl orange and phenolphthalein. I know that methyl orange is the most suitable indicator. What I don't know is how do I go about making a procedure for this titration? I was told that I had to use a buffer solution and a pH meter. Any suggestions? 020608

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Tests

• Acid-base equilibria (A2)

updated: 09 July 2003