Education Journalist | Study Abroad Lead
Lead (IV) Acetate formula, also known as lead tetraacetate, is a chemical compound with the chemical formula Pb(C2H3O2)4. It is a colourless solid that is soluble in nonpolar organic solvents, indicating that it is not a salt. The moisture in the air degrades or spoils it, and it is typically stored with additional acetic acid. The compound is effective in the organic synthesis process.
| Table of Content |
Key Terms: Lead (IV) Acetate, Lead Tetraacetate, Acetic Acid, Ions, Oxygen, Crystals, Carboxylic Acids, Lead, Organolead Compounds
Lead (IV) Acetate: Structure and Formula
[Click Here for Sample Questions]
The Lead (IV) centres in the solid-state are synchronized by four acetate ions, which are bidentate and coordinated by two oxygen atoms at a time. The lead atom has 8 coordinates, and the O atoms combine to form a flattened trigonal dodecahedron. Here is an image of its chemical structure in the common representations that are used for organic molecules:
Structure of Lead (IV) Acetate
Also Read:
Properties of Lead (IV) Acetate
[Click Here for Previous Year's Questions]
Lead IV Acetate appears pink or sometimes as colourless crystals. It has a melting point of about 175 °C and decomposes at the boiling point. Furthermore, the density of lead IV acetate is close to 2.228 g/cm3. It also has a molar mass of 443.376 g/mol. It dissolves in water because it is soluble in water. It is, however, soluble in hot glacial acetic acid, benzene, chloroform, tetra-chloro ethane, and nitrobenzene.
Lead (IV) Acetate
Lead (IV) Acetate: Reagent in Organic Chemistry
[Click Here for Sample Questions]
Lead tetraacetate is a long-lasting and powerful oxidizing agent, as well as a source of acetyloxy groups and a general reagent for introducing lead into organolead compounds. Some of its applications in organic chemistry include
- Acetylation of benzylic, allylic, and α-oxygen ether C-H bonds, as in the photochemical conversion of dioxane to 1,4-dioxane via the 2-acetoxy-1,4-dioxane intermediate and the transformation of α-pinene to verbenone.
- In the Hofmann reorganization, an alternative reagent to bromine.
- Hydrazone oxidation to diazo compounds, such as hexafluoroacetone hydrazone to bis (trifluoromethyl) diazomethane.
- Aziridine formation, such as the reaction of N-aminophthalimide and stilbene.
- Cleavage of α-hydroxy acids or 1,2 diols to their corresponding aldehydes or ketones, which frequently replaces ozonolysis, as in the oxidation of di-n-butyl d-tartrate to n-butyl glyoxylate.
- The reaction with alkenes produces γ-lactones.
- The cyclic ethers are formed by the oxidation of alcohols containing a δ-proton.
- Oxidative cleavage of definite allyl alcohols in the presence of ozone.
- Acetophenone to phenylacetic acid conversion.
- The Kochi reaction decarboxylates carboxylic acids to alkyl halides.
Safety Measurements for Lead (IV) Acetate
[Click Here for Previous Year's Questions]
- When we ingest, inhale, or absorb lead (IV) acetate through our skin, it can be fatal.
- It can irritate a living being's skin and also affect the eyes and respiratory tract at the same time.
- It is also a neurotoxin.
- Furthermore, it affects the gum tissue, the central nervous system, the kidneys, blood vessels, and blood itself, as well as the human reproductive system.
Also Read:
Things to Remember
- Lead (IV) Acetate, also known as lead tetraacetate, is a colourless solid with the chemical formula Pb(C2H3O2)4. It is easily degraded by moisture and is typically stored with additional acetic acid.
- Lead (IV) Acetate crystals are pink or sometimes colourless. It melts at about 175 °C and decomposes at the nailing point.
- It acts as a powerful oxidizing agent with a long half-life, and a general reagent for introducing lead into organolead compounds as well as a source of acetyloxy groups.
- Lead (IV) Acetate has an effect on the gum tissue, the central nervous system, the kidneys, blood vessels, the blood itself, and the human reproductive system.
Sample Questions
Ques. What is the reaction for preparing Lead IV Acetate, i.e. Pb(C2H3O2)4? (3 Marks)
Ans. It is typically made by reacting red lead with acetic acid and acetic anhydride, i.e. Ac2O, which absorbs water (H2O). The overall reaction is as follows:
Pb3O4 + 4 Ac2O = Pb(OAc)4 + 2 Pb(OAc)2
The remaining lead (II) acetate can be easily partially oxidized to tetraacetate, as shown in the reaction below:
2 Pb(OAc)2 + Cl2 → Pb(OAc)4 + PbCl2
Ques. Explain why an organic compound was fused with metallic sodium to test nitrogen, sulfur, and halogens. Why does an organic liquid evaporate at a temperature lower than its boiling point during steam distillation? (3 Marks)
Ans. Organic compounds are fused with sodium metal, resulting in the formation of NaCN, Na2S, NaX, and Na3PO4. Because these are ionic compounds, they become more reactive and can thus be easily tested with appropriate reagents.
Since the sum of the vapour pressures of organic compounds and steam in steam distillation should equal atmospheric pressure.
Ques. Why is (CH3)3C+ more stable than CH3C + H2? Explain why an organic compound is fused with sodium in order to test nitrogen, halogens, and sulfur. (3 Marks)
Ans. Because (CH3)3C+ contains nine alpha hydrogens and nine hyperconjugation structures, whereas CH3C + H2 contains three alpha hydrogens and three hyperconjugation structures, (CH3)3C+ is more stable than CH3C + H2.
When elements in an organic compound are fused with sodium metal, they are converted into sodium salts that are water-soluble and can be filtered and detected using the appropriate tests.
Ques. Describe the hyperconjugation effect. How does the hyperconjugation effect explain alkene stability? (3 Marks)
Ans. The number of no-bond resonance structures that can be written for various classes of carbonium ions may explain their relative stability. Such structures are created by shifting the bonding electrons from an adjacent C-H bond to the electron-deficient carbon, causing the positive charge that was previously on carbon to be dispersed to the hydrogen. Hyperconjugation refers to the process of releasing electrons by assuming no bond character in the adjacent C-H bond. The greater the hyperconjugation, the greater the stability of alkenes.
Ques. Explain the paper chromatography principle. Why is nitric acid added to sodium extract before silver nitrate is added for halogen testing? (3 Marks)
Ans. This is the most basic type of chromatography. A strip of paper serves as an adsorbent in this case. It works on the principle of partial adsorption. The paper is made of cellulose fibres with water molecules adsorbed on them. This serves as the stationary phase. The mobile phase is a solvent-prepared mixture of the components to be identified.
To decompose the sodium extract, nitric acid is added.
NaCN + HNO3 ——> NaNO3 + HCN
Na2S + 2HNO3 ——> 2NaNO3 + H2S
Ques. Distinguish between the principles of estimating nitrogen in an organic compound using the Dumas method and the Kjeldahl method. (3 Marks)
Ans. Dumas Method: The organic compound is heated strongly with an excess of CuO'(Cupric Oxide) in an atmosphere of CO2 until free nitrogen, CO2, and H2O are obtained using the Dumas method.
Kjeldahl's Method: A known mass of an organic compound is strongly heated with a cone. H2SO4, a trace of potassium sulfate, and a trace of mercury (a catalyst). The nitrogen in the organic compound is converted to ammonium sulfate as a result of the reaction.
Ques. What is the difference between electrophiles and nucleophiles? Explain using examples. (3 Marks)
Ans. Electrophiles: Electrophile is a word that means "lovers of electrons." Electrophiles are electron-poor. They could be either positive ions or neutral molecules. Eg: H+, Cl+, Br+, NO2+, R3C+, RN2+, AlCl3, BF3
Nucleophiles: The name nucleophiles mean "nucleus loving," and it refers to an enzyme that attacks low electron density regions (positive centres) in a substrate molecule. They have a lot of electrons and can be negative ions or neutral molecules. Eg: Ex: Cl– Br–, CN–, OH–, RCR2–, NH3, RNH2, H2O, ROH etc.
Also Read:
Comments