Lead

Lead does not react with sulphuric acid, due to the passivated PbO surface.

Lead reacts slowly with hydrochloric acid, HCl and nitric acid, HNO₃.

Pb(s) + 2 HCl(aq) Pb²⁺(aq) + 2 Cl⁻(aq) + H₂(g)
Pb(s) + 2 HNO₃(aq) Pb²⁺(aq) + 2 NO₃⁻(aq) + H₂(g)

Lead reacts with air, in the presence of moist and carbon dioxide, forming a passivating layer. The layer is most likely lead hydroxy carbonate [8].

When heated in a stream of air, lead burns [8]:

2 Pb(s) + O₂(g) 2 PbO(s)

Lead dissolves slowly in cold alkalis to form plumbites.

Pb(II) reacts with hydroxide forming lead(II) oxide. The oxide is soluble in excess hydroxide, forming a lead hydroxide complex

Pb²⁺(aq) + 2 OH⁻(aq) + x H₂O(l) PbO · (x+1) H₂O(s)

PbO · x H₂O(s) + OH⁻(aq) [Pb(OH)₃]⁻(aq) + (x-1) H₂O(l)

Lead(II) is precipitated by chromate under acidic conditions.

Pb²⁺(aq) + CrO₄²⁻(aq) PbCrO₄(s) [yellow]

Lead reacts vigorously with fluorine, F₂, at room temperature, and chlorine, Cl₂, when heated, forming the corresponding lead(II) halides [8].

Pb(s) + F₂(g) PbF₂(s)
Pb(s) + Cl₂(g) PbCl₂(s)


Lead(II) is precipitated by chloride, bromide and iodide ions under cold neutral to acidic conditions. In concentrated hydrochloric acid, the chloride precipitate is dissolved. Solubility of the salts decrease with increasing periods:

Pb²⁺(aq) + 2 Cl⁻(aq) PbCl₂(s) [white]
PbCl₂(s) + 2 Cl⁻(aq) [PbCl₄]⁻(aq)

Pb²⁺(aq) + 2 Br⁻(aq) PbBr₂(s) [white]

Pb²⁺(aq) + 2 I⁻(aq) PbI₂(s) [yellow]

Lead(IV) is a strong oxidizing agent:

PbO₂(s) + 2 Ce³⁺(aq) + 4 H⁺(aq) + 12 NO₃⁻(aq) Pb²⁺(aq) + 2 [Ce(NO₃)₆]²⁻(aq) + 2 H₂O(l)

2 Mn²⁺(aq) + 5 Pb₃O₄(s) + 24 H⁺(aq) MnO₄⁻(aq) + 15 Pb²⁺(aq) + 12 H₂O(l)

Lead(II) is precipitated by sulfate under neutral to acidic conditions. The precipitate is partially soluble in concentrated sulfuric acid and dilute nitric acid and highly soluble in hot sodium hydroxide or acetate buffer:

Pb²⁺(aq) + SO₄²⁻(aq) PbSO₄(s) [white]
PbSO₄(s) + 3 OH⁻(aq) [Pb(OH)₃]⁻(aq) + SO₄²⁻(aq)
Pb²⁺(aq) + 2 Ac⁻(aq) PbAc₂(aq) + SO₄²⁻(aq)

Lead(II) is precipitated by sulfide in 0.4 M hydrochloric acid. During the process, red or brown intermediates can sometimes be observed:

Pb²⁺(aq) + H₂S(aq) PbS(s) [black] + H₂(g)

When heated, lead reacts with sulfur [8]:

Pb(s) + S(s) PbS(s)

Lead does not react with water in the absence of air. In the presence of air, lead(II) hydroxide is formed [8]:

2 Pb(2) + 2 H₂O(l) + O₂(g) 2 Pb(OH)₂(s)

Method 3500-Pb C Inductively Coupled Plasma Method [6]. A portion of the sample is digested in a combination of acids. The digest is aspirated into an 8,000 K argon plasma where resulting light emission is quantified for 30 elements simultaneously.

Method limit of detection in water = 0.01 mg/L
Method limit of detection in soil = 2.00 mg/kg