Edexcel IGCSE Chemistry 復習筆記 2.8.3 Tests for Cations
Tests for Cations
Metal cations in aqueous solution can be identified by the?colour?of the precipitate they form on addition of sodium hydroxide and ammonia
If only a small amount of NaOH is used then normally the?metal hydroxide?precipitates
?Analysing results
The table below contains the results for each of the cations included in the syllabus
If a precipitate is formed from NaOH then the hydroxide is insoluble in water
Testing for Cations Table
Exam Tip
Sometimes you may not see much of a precipitate because the cation you are testing is present is very small amounts. However, every a slight cloudiness or colour change can indicate a positive test result.