Neutralisation & Titrations 2
Chemistry: AQA GCSE Higher, topic 4.3.10
Titrations
Titration is a technique that measures the volumes of acid and alkali solutions that are needed in a neutralisation reaction.
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Key variables
- If, for example, we were neutralising an alkali with an acid, titration could be used to calculate the concentration of the alkali if we knew:
- The concentration of the acid to be added.
- The volume of the alkali.
Indicators
- Indicators show the end point of titrations by suddenly changing colour when the solution turns from acidic to alkaline, or alkaline to acidic.
Choosing an indicator
- When choosing an indicator, the strength of the acid and alkali must be considered.
- If both the acid and alkali are strong, suitable indicators would be:
- Methyl orange (yellow in alkali → red in acid).
- Phenolphthalein (pink in alkali → colourless in acid).
Test yourself on Neutralisation & Titrations 2
How do methyl orange and phenolphthalein differ when a solution changes from alkaline to acidic?
A student is titrating a strong acid with a strong alkali. Which indicator would be a suitable choice?
Select the correct statement in each pair.
What does an indicator's sudden colour change show during a titration?