Composed of the ion lead

The cation Pb2+ belongs to the first group of cations in the diagram of qualitative analysis.

The system lead-oxygen

  • the Pb oxide derived from Pb+2 has two crystalline forms:
    • an Orthorhombic form : the yellow Litharge
    • a Quadratic form red

  • the Minium Pb3O4 whose color can vary with the report/ratio n \ quad = \ quad \ frac {} {}

    • If N = 1,33, the color is orange and we have Pb3O4, or PbO22PbO.
    • When N increases, the color becomes darker until the limit of n=1,54

  • the Oxide lead (PbO2) corresponds to state IV of lead

Compounds of lead II

  • the strong bases form with the Pb2+ cation a white precipitate of Hydroxyde of lead or Acide plombous which is insoluble in the Ammoniac:
    • Pb^ {2+} \ quad +2NaOH \ quad \ to \ quad 2Na^ {+} \ quad + \ quad Pb (OH) _ {2} \ downarrow or H_2PbO_2
      .
    • the Acide plombous reacts with an excess of Hydroxyde of sodium to form soluble Plombite of sodium.
    • H_ {2} PbO {2} \ quad+2NaOH \ quad \ to \ quad Na_ {2} PbO_ {2} \ downarrow \ quad+ \ quad 2:00 _ {2} O

  • the chlorides precipitate the phosgenite:
    • Pb^ {2+} +2Cl^ {-} \ quad \ to \ quad PbCl_ {2} \ downarrow
    • This precipitate is soluble in warm water what makes it possible to separate the cations lead (II) and money.

  • the sulphuric Acid precipitates the Pb2+ cation in Sulfate of white lead:
    • Pb^ {2+} \ quad + \ quad SO_ {4} ^ {2} \ quad \ to \ quad PbSO_ {4} \ downarrow
    • This dissolved precipitate in the strong bases hot being formed Plumbite S:
    • PbSO_ {4} \ quad + \ quad 4NaOH \ quad \ to \ quad Na_ {2} PbO_ {2} \ quad + \ quad Na_ {2} SO_ {4} \ quad + \ quad 2:00 _ {2} O
      .
    • the presence of HCl or HNO3 increases the solubility of PbSO4 per formation of the HSO4- anion according to the reaction:
    • 2PbSO_ {4} \ quad + \ quad 2HNO_ {3} \ quad \ to \ quad Pb (HSO_ {4}) _ {2} \ quad + \ quad Pb (NO_ {3}) _ {2}

  • the chromates and bichromates form a Chromate of lead yellow far from water soluble, soluble in the strong bases, insoluble in ammonia and the acetic Acid .
    • Pb^ {2+} \ quad +CrO_ {4} ^ {2} \ quad \ to \ quad PbCrO_ {4} \ downarrow
    • 2Pb^ {2+} \ quad + \ quad Cr_ {2} O_ {7} ^ {2} \ quad + \ quad H_ {2} O \ quad \ to \ quad 2PbCrO_ {4} \ downarrow \ quad + \ quad H^ {+}

  • the iodides form with the cation lead the yellow precipitate of Iodure of lead
    • Pb^ {2+} \ quad + \ quad 2I^ {-} \ quad \ to \ quad PbI_ {2} \ quad \ downarrow

  • the ion hydrogénophosphate HPO4-2 gives with the ion Pb2+ a white precipitate of Phosphate of lead:
    • 3Pb^ {2+} \ quad + \ quad 4HPO_ {4} ^ {2} \ quad \ to \ quad Pb_ {3} (PO_ {4}) _ {2} \ downarrow \ quad + \ quad 2:00 _ {2} PO_ {4} ^ {-}

  • the Hydrogen peroxide oxide lead hydroxide in Dioxide of lead PbO2 of brown color:
    • Pb (OH) _ {2} \ quad +H_ {2} O_ {2} \ quad \ to \ quad PbO_ {2} \ quad + \ quad 2:00 _ {2} O

  • the PbS sulfide is formed under the action of H2S on a solution of Pb2+

Compounds of lead IV

  • Derivatives organoplombic
    • tetraethyl Lead obtained by the action of the Chloride ethyl on the alloy Pb-Na
    • 4Pb-Na \ quad + \ quad 4C_ {2} H_ {5} Cl \ quad \ to \ quad Pb (C_ {2} H_ {5}) _ {4} \ quad + \ quad 4NaCl \ quad +3Pb
    • the tetramethyl Lead

  • Halogénure
    • the Tétrachlorure of lead PbCl4 is very unstable and breaks up:

    • PbCl {4 \ quad} \ to \ quad PbCl_ {2} \ quad + \ quad Cl_ {2}

  • Acetate: the attack of Pb3O4 by the acetic Acid followed by a Oxydation by the Chlore gives the Tétra-acetate of red lead of color according to the reactions:
    • Pb_ {3} O_ {4} \ quad + \ quad 8HCH_ {3} COO \ quad \ to \ quad Pb (CH_ {3} COO) _ {4} \ quad + \ quad 2Pb (CHCOO) _ {2} \ quad + \ quad 4:00 _ {2} O
    • 2Pb (CH_ {3} COO) _ {2} \ quad + \ quad Cl_ {2} \ quad \ to \ quad Pb (CH_ {3} COO) _ {4} \ quad + \ quad PbCl_ {2}

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