Identifying negative ions - Carbonates test (Edexcel GCSE Chemistry): Flashcards

$CO_3^{2-}$ (carbonate ions)

Carbon dioxide ($CO_2$)

Add dilute hydrochloric acid ($HCl$)

Fizzing

Bubble through limewater

Limewater turns cloudy

Can neutralise limewater and ruin test

Could contaminate the test

Minimal amount (more sensitive & accurate)

$CaCO_3$ and $HCl$

$CaCl_2$, $CO_2$, $H_2O$

$CaCO_3 + 2HCl \rightarrow CaCl_2 + CO_2 + H_2O$