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
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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.
FAQs on Lead IV Oxide
1. What exactly is Lead (IV) oxide?
Lead (IV) oxide is an inorganic compound with the chemical formula PbO₂. It is also known by other names like lead dioxide or plumbic oxide. It typically appears as a dark-brown, crystalline powder that does not dissolve in water.
2. What are the most common uses of Lead (IV) oxide in everyday life?
Lead (IV) oxide is a powerful oxidising agent with several key applications. Its most important uses are:
- In lead-acid batteries, like those found in cars, where it forms the positive electrode (cathode).
- In the production of safety matches and pyrotechnics.
- As a curing agent for certain types of polymers.
- As a pigment in some specialised industrial paints.
3. What is the main difference between Lead (II) oxide (PbO) and Lead (IV) oxide (PbO₂)?
The key difference is the oxidation state of the lead atom. In Lead (II) oxide (PbO), lead has an oxidation state of +2. In Lead (IV) oxide (PbO₂), lead is in a +4 oxidation state. This affects their properties; for instance, PbO is usually yellow or red, whereas PbO₂ is dark brown.
4. Why is the compound called Lead (IV) oxide? What does the Roman numeral (IV) signify?
The Roman numeral (IV) in the name indicates the oxidation state (or charge) of the lead atom in the molecule. In PbO₂, there are two oxygen atoms, each with a -2 charge. To create a neutral compound, the single lead atom must have a charge of +4. This naming convention helps differentiate it from other lead oxides like Lead (II) oxide.
5. How does Lead (IV) oxide behave chemically? Is it an acidic or basic oxide?
Lead (IV) oxide is classified as an amphoteric oxide. This is a special characteristic which means it can react with both acids and strong bases. While it generally shows more acidic character, its ability to react as either is a key property for a metal oxide with a high oxidation state.
6. How does Lead (IV) oxide actually work inside a car battery?
In a typical lead-acid battery, Lead (IV) oxide (PbO₂) paste is applied to a grid to form the positive electrode, or cathode. When you use the battery, the PbO₂ reacts with sulfuric acid and the lead from the negative electrode. This chemical reaction produces lead sulfate, water, and most importantly, releases electrical energy to power the car.
7. Is there a difference between Lead (IV) oxide (PbO₂) and red lead (Pb₃O₄)?
Yes, they are different compounds. Lead (IV) oxide is PbO₂. Red lead, with the formula Pb₃O₄, is a mixed-valence compound. It is more accurately thought of as a combination of two molecules of Lead (II) oxide and one molecule of Lead (IV) oxide (2PbO·PbO₂). They have different colours and chemical properties.
