हिंदी

Analysis of Cations - Analysis of Group-I Cations

Advertisements

Topics

Estimated time: 3 minutes
CBSE: Class 12

Key Points: Analysis of Group I Cations

Analysis of Group I Cations (Pb²⁺, Ag⁺, Hg₂²⁺):

Reagent: dil. HCl; precipitate: AgCl, PbCl₂, Hg₂Cl₂ (all white)

PbCl₂ is soluble in hot water (distinguishes Pb²⁺ from Ag⁺ and Hg₂²⁺)

On residue (AgCl + Hg₂Cl₂): add NH₄OH:

  • Ag⁺ → Ag(NH₃)₂Cl (soluble, colourless)
  • Hg₂²⁺ → Hg + Hg(NH₂)Cl (black precipitate)

Test for Pb²⁺:

  • K₂CrO₄ → yellow ppt. of PbCrO₄ (soluble in hot NaOH)
  • KI → yellow ppt. of PbI₂ (reversible on cooling)
  • dil. H₂SO₄ → white ppt. of PbSO₄
  • H₂S → black ppt. of PbS
  • NH₃ solution → white ppt. of Pb(OH)₂ (soluble in excess NaOH → [Pb(OH)₄]²⁻, amphoteric)
Advertisements
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×