📖 Cation Analysis Table▼

Identification of metal cations using Sodium Hydroxide (NaOH) and Ammonium Hydroxide (NH₄OH) solutions by observing precipitate color and solubility in excess reagent.

CationWith NaOH (Few drops)With NaOH (Excess)With NH₄OH (Few drops)With NH₄OH (Excess)
Cu²⁺Pale blue pptInsolublePale blue pptSoluble (Deep blue soln)
Fe²⁺Dirty green pptInsolubleDirty green pptInsoluble
Fe³⁺Reddish brown pptInsolubleReddish brown pptInsoluble
Pb²⁺White (chalky) pptSolubleWhite pptInsoluble
Zn²⁺White (gelatinous)SolubleWhite pptSoluble

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Sodium Hydroxide (NaOH)
Ammonium Hydroxide (NH₄OH)

Work systematically: add a few drops first and note the precipitate colour, then add the same reagent in excess to test solubility. Reset before switching reagents.

Safety Notes

  • Wear eye protection: sodium hydroxide and ammonia solution are corrosive/irritant.
  • Add reagents dropwise and keep the test tube pointed away from yourself and others.
  • Do not inhale ammonia directly; waft gently if instructed to smell it.
  • Treat all metal-salt solutions (Cu, Fe, Pb, Zn) as toxic/irritant; collect waste as directed, especially lead solutions.
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Working Inference

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Run at least two tests, choose a likely cation, and write your evidence before revealing the identity.
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