EDEXCEL IGCSE CHEMISTRY: DOUBLE SCIENCE 复习笔记：2.7.3 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
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
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.