Ch 08 - Aldehydes, Ketones and Carboxylic Acids12th Chemistry
Structure of the Carbonyl Group
What is the hybridization, geometry, and approximate bond angle of the central carbon atom in a carbonyl group?
What is the hybridization, geometry, and approximate bond angle of the central carbon atom in a carbonyl group?
Structural Properties:
- Hybridization: The carbonyl carbon is strictly hybridized.
- Geometry: It forms a trigonal planar (coplanar) structure, meaning the carbon, oxygen, and the two attached atoms all lie in the exact same geometric plane.
- Bond Angle: The bond angles are approximately .
Bonding Nature:
- The carbon-oxygen double bond consists of one sigma () bond and one pi () bond.
- The -electron cloud sits completely above and below the plane of the molecule.
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Polarity of the Carbonyl Group
Why are carbonyl compounds highly polar, and how does this dictate the distinct reactive centers of the molecule?
Why are carbonyl compounds highly polar, and how does this dictate the distinct reactive centers of the molecule?
The Polarity Mechanism:
- The carbon-oxygen double bond is highly polarized due to the higher electronegativity of oxygen relative to carbon.
- This polarity is stabilized by resonance between a neutral structure and a dipolar structure ().
Reactive Centers:
- Carbonyl Carbon: Acquires a partial positive charge (), making it an electrophilic (Lewis acid) center prone to nucleophilic attack.
- Carbonyl Oxygen: Acquires a partial negative charge (), making it a nucleophilic (Lewis base) center.
Prism Memory Hook
Oxygen is greedy (Nucleophilic), Carbon is needy (Electrophilic).
Common Nomenclature of Ketones
What is the historical common name for the simplest dimethyl ketone, and how are alkyl phenyl ketones generally named?
What is the historical common name for the simplest dimethyl ketone, and how are alkyl phenyl ketones generally named?
Key Common Names:
- Dimethyl Ketone: Historically known universally as Acetone ().
Alkyl Phenyl Ketones:
- They are usually named by adding the name of the acyl group as a prefix to the word phenone.
- Examples:
- = Acetophenone (Methyl phenyl ketone)
- = Propiophenone (Ethyl phenyl ketone)
- = Benzophenone (Diphenyl ketone)
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Also in this chapter
56 more cards to study in Prism
- 4Preparation: Hydration of Alkynes
- 5Boiling Points of Carbonyls vs Alcohols
- 6Rosenmund Reduction
- 7Stephen Reaction
- 8Rosenmund Reduction: Formaldehyde Exception
- 9Reduction by DIBAL-H
- 10Etard Reaction
- 11Oxidation of Toluene using $CrO_3$
- 12Gatterman-Koch Formylation
- 13Preparation of Ketones from Acyl Chlorides
- 14Ketones from Nitriles & Grignard Reagents
- 15Friedel-Crafts Acylation
- 16Dialkylcadmium vs Grignard Reagent
- 17Mechanism of Nucleophilic Addition
- 18Role of Acid Catalyst in Nucleophilic Addition
- 19Addition of HCN (Cyanohydrin Formation)
- 20Reactivity: Aldehydes vs Ketones
- 21Addition of Sodium Hydrogensulphite ($NaHSO_3$)
- 22Reactivity: Aromatic vs Aliphatic Aldehydes
- 23Addition of Alcohols: Hemiacetals and Acetals
- 24Addition of Ethylene Glycol to Ketones
- 25Nucleophilicity of Semicarbazide
- 26Geometrical Isomerism in Oximes
- 27Clemmensen Reduction
- 28Wolff-Kishner Reduction
- 29Haloform Reaction (Iodoform Test)
- 30Acidity of Alpha-Hydrogens
- 31Aldol Condensation Reaction
- 32Cross Aldol Condensation Product Distribution
- 33Cannizzaro Reaction
- 34Cross-Cannizzaro Reaction Predictability
- 35Oxidation of Alkylbenzenes
- 362,4-DNP Test (Brady's Reagent)
- 37Carboxylic Acids from Grignard Reagents
- 38Tollens' Test (Silver Mirror Test)
- 39Fehling's Test
- 40Differentiating Aldehydes & Ketones (Summary)
- 41Electrophilicity of the Carboxyl Carbon
- 42Formation of Acyl Chlorides
- 43Dimerization of Carboxylic Acids
- 44Fischer-Speier Esterification
- 45Reaction of Carboxylic Acids with Ammonia
- 46Reduction of Carboxylic Acids
- 47Decarboxylation
- 48Acidity: Carboxylic Acids vs Phenols
- 49Hell-Volhard-Zelinsky (HVZ) Reaction
- 50Substituent Effects on Acid Strength
- 51Ring Substitution in Aromatic Acids
- 52Sodium Bicarbonate Test for Acids
- 53Commercial Uses of Carboxylic Acids
- 54Tollens' Test Anomaly: Methanoic Acid
- 55Dry Distillation of Calcium Salts
- 56Ferric Chloride ($FeCl_3$) Test
- 57Hydrolysis of Cyanides (Nitriles)
- 58Esterification via Diazomethane
- 59Formation of Cyclic Anhydrides
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