[Chemistry Class Notes] Lead IV Oxide Pdf for Exam

What is lead IV oxide?

Lead (IV) oxide is the compound with an oxidation state of +4, which appears as dark-brown solid which is insoluble in water. PbO2 exists in two crystalline forms. It has wide applications in electrochemistry, especially as the positive plate of lead acid batteries.

Chemical Formula:  PbO2 or O2Pb

IUPAC Name:  Lead (IV) oxide

lead IV Oxide Formula Weight: 239.19gms

Synonyms:

• Lead Dioxide

• Lead (IV) oxide

• Lead peroxide

• lead (IV) oxide

• Plumbic oxide

• Plattnerite

Structure: Lead IV Oxide Has A Crystal Hexagonal Structure

(Image to be added soon)

Lead dioxide exists in two major polymorphs, they are alpha and beta, which occur naturally as rare minerals scrutinyite and plattnerite.

Molecular Structure of PbO2

Properties of lead IV oxide

Physical Properties:

• The Molar mass of lead oxide is 239.1988 g/mol

• It appears with dark-brown color or in black powder

• Lead oxide has a density of 9.38 g/cm3

• Its Melting point is 290 °C (554 °F; 563 K)

• Solubility: It is insoluble in water and alcohol and soluble in acetic acid

Chemical Properties:

Let,s check some of the lead iv oxide chemical reactions

Decomposition:

When Lead dioxide is heated in air, it decomposes as follows:

24 PbO2 → 2 Pb12O19 + 5 O2

Pb12O19 → Pb12O17 + O2

2 Pb12O17 → 8 Pb3O4 + O2

2 Pb3O4 → 6 PbO + O2

Reaction With Acids And Bases:

Lead dioxide (PbO2) is an amphoteric compound with prevalent acidic properties.  hydroxy plumbate ion, [Pb(OH)6]2− is formed when lead oxide is dissolved in strong base.

PbO2 +  NaOH + 2 H2O → Na2[Pb(OH)6]

lead dioxide reacts with hot acids, since Pb4+ cation is very instable, it converts in to stable Pb2+ state and oxygen is liberated.

2PbO2 + 2H2SO4 → 2PbSO4 + 2H2O + O2

2PbO2 + 4HNO3 → 2Pb(NO3)2 + 2H2O + O2

PbO2 + 4HCl → PbCl2 + 2H2O + Cl2

Oxidising Agent:

Lead dioxide is familiar for its strong oxidizing properties, 

MnSO4 + 5 PbO2 + 6 HNO3 → 2 HMnO4 + PbSO4 +  Pb (NO3)2 + 2 H2O

Cr (OH)3 + 10 KOH + 3 PbO2 → K2CrO4 + K2PbO2 + 8 H2O

Production of lead IV oxide:

The reaction of Pb3O4 with nitric acid produces the dioxide.

Pb3O4 + HNO3 → PbO2 + Pb (NO3)2 + H2O

Plumbic oxide is treated, when lead chloride is treated with sodium hypochlorite (NaClO).

Lead IV Oxide PbO2 Uses:

• Lead dioxide is used in the manufacture of matches, pyrotechnics, the curing of sulfide polymers and dyes.

• It is also used in the development of high-voltage lightning arresters

• lead dioxide anodes were used for the production of glyoxylic acid from oxalic acid in a sulfuric acid electrolyte.

• It is used as the cathode of lead acid batteries.

Key Points:

Lead (IV) oxide is an inorganic compound which is amphoteric in nature and has an oxidation state of +4. Lead dioxide exists in two major polymorphs, they are alpha and beta, which occur naturally as rare minerals scrutinyite and plattnerite.

It is insoluble in water and alcohol and soluble in acetic acid. It decomposes when it is heated in air. It possesses strong oxidizing properties. It is used in various ways, the most important use is, it is used as a cathode in lead acid batteries.