Systematic Analysis of Inorganic Salts

Study Notes

Color observations can indicate specific metal ions:
- Blue suggests presence of Cu²⁺
- Pink indicates Mn²⁺
- Colorless implies absence of both Cu²⁺ and Mn²⁺.
Smell analysis can reveal potential anions:
- Vinegar smell suggests presence of CH₃COO⁻ or NH₄⁺.
- Ammonia smell is indicative of NH₄⁺.
Adding sodium carbonate produces a clear solution confirming presence of NH₄⁺.
Heating the salt results in various observations:
- Colorless gas with ammonia smell suggests NH₄⁺ presence.
- Yellow when hot and white when cold indicates Zn²⁺.
- Vinegar smelling vapors and a colorless gas turning lime water milky imply presence of CH₃COO⁻ and CO₃²⁻, respectively.
- Reddish-brown vapors suggest NO₃⁻ presence.
- No notable reactions mean absence of NH₄⁺, Zn²⁺, CH₃COO⁻, CO₃²⁻, and NO₃⁻.
Flame tests can identify specific cations:
- Pale green flame suggests Ba²⁺ presence.
- Crimson red indicates Sr²⁺.
- Brick red flame represents Ca²⁺.
- Absence of color indicates no Ba²⁺, Sr²⁺, or Ca²⁺.
Ash test with cobalt nitrate can reveal cations:
- Blue tinted ash suggests Al³⁺.
- Green tinted ash indicates Zn²⁺.
- Pink tinted ash represents Mg²⁺.
- Lack of color implies absence of Al³⁺, Zn²⁺, and Mg²⁺.

Reaction with dilute HCl causes brisk effervescence, showing presence of CO₃²⁻ due to evolution of CO₂ gas.
Rubbing the salt with dilute H₂SO₄ releases a vinegar smell, confirming presence of CH₃COO⁻.
Heating the salt with concentrated H₂SO₄ produces a colorless fuming gas that creates dense white fumes when wet glass is introduced, indicating presence of Cl⁻.
Heating the salt along with copper turnings results in reddish-brown vapors and a blue solution, confirming presence of NO₃⁻.
Interaction with BaCl₂ leads to the formation of a thick white precipitate, suggesting sulfate ions are absent.