Qualitative Analysis: Group 5 Cations ($$\text{Ca}^{2+}, \text{Ba}^{2+}$$)

Formula / Core Reaction:

$$\text{M}^{2+} + (\text{NH}_4)_2\text{CO}_3 \xrightarrow{\text{NH}_4\text{OH}} \text{MCO}_3 \downarrow \quad (\text{M} = \text{Ca}, \text{Ba})$$

$$\text{Ca}^{2+} \xrightarrow{\text{Flame}} \text{Brick Red Flame}, \qquad \text{Ba}^{2+} \xrightarrow{\text{Flame}} \text{Apple Green Flame}$$

Concept: Group 5 cations precipitate as insoluble carbonates using $$(\text{NH}_4)_2\text{CO}_3$$ in basic medium. Individual cations are differentiated by characteristic flame emission spectra due to electronic excitation.

Notation / Key Observation:

• Group Reagent: $$(\text{NH}_4)_2\text{CO}_3$$ in presence of $$\text{NH}_4\text{OH}$$;
• $$\text{Ca}^{2+}$$ Flame: Brick red;
• $$\text{Ba}^{2+}$$ Flame: Apple green.