Edexcel IGCSE Chemistry 2.28 indicator tests for acids and alkalis
Practise indicator-test questions by recalling litmus, methyl orange and phenolphthalein colours in acids, alkalis and endpoints.
- Syllabus
- First assessment 2019
- Course
- Chemistry 4CH1
Exam points
- Recall litmus, methyl orange and phenolphthalein colours in acidic or alkaline solutions.
- Give endpoint colour changes in the correct order for a named indicator and titration.
2.28 Acid–base indicators question 1
Sodium hydroxide dissolves in water, forming a strongly alkaline solution.
Ammonia dissolves in water, forming a slightly less alkaline solution.
When ammonia solution reacts with sulfuric acid, a neutralisation reaction occurs and ammonium sulfate forms.
The diagram shows a beaker containing some ammonia solution and a few drops of phenolphthalein indicator.
Dilute sulfuric acid is added to the beaker until it is in excess.
What are the colours of the phenolphthalein indicator before and after adding excess sulfuric acid?
Before
After
orange
red
yellow
red
pink
colourless
colourless
pink
All question bank results loaded