What bond defines the carbonyl group?
A carbon–oxygen double bond, >C=O.
Which atoms are bonded to an aldehyde carbonyl carbon?
One carbon atom and one hydrogen atom.
Which atoms are bonded to a ketone carbonyl carbon?
Two carbon atoms.
Why is the carbonyl bond polar?
Oxygen is more electronegative than carbon.
What are the electrophilic and nucleophilic sites in a carbonyl group?
The carbonyl carbon is electrophilic, and the oxygen is nucleophilic.
How are open-chain aliphatic aldehydes named from their corresponding alkanes?
Replace the alkane ending -e with -al.
How are open-chain aliphatic ketones named from their corresponding alkanes?
Replace the alkane ending -e with -one.
From which end are aldehyde chains numbered?
From the aldehyde carbon.
From which end are ketone chains numbered?
From the end nearest the carbonyl group.
What do primary and secondary alcohols form upon oxidation?
Primary alcohols form aldehydes, while secondary alcohols form ketones.
How do aldehyde and ketone boiling points compare with hydrocarbons and ethers of similar molecular mass?
They are higher because of dipole–dipole association.
How do aldehyde and ketone boiling points compare with alcohols of similar molecular mass?
They are lower because they lack intermolecular hydrogen bonding.
How do lower aldehydes and ketones dissolve in water?
They are miscible with water in all proportions.
How does water solubility change as the alkyl chain grows in aldehydes and ketones?
It decreases rapidly.
What happens to the carbonyl carbon during nucleophilic addition?
It changes from to as a tetrahedral alkoxide forms.
What is the first step in nucleophilic addition to a carbonyl?
A nucleophile attacks the electrophilic carbonyl carbon.
Why are aldehydes generally more reactive than ketones in nucleophilic addition?
Ketones have greater steric hindrance and their two alkyl groups reduce carbonyl-carbon electrophilicity more strongly.
What products form when aldehydes and ketones are reduced with sodium borohydride, lithium aluminium hydride, or catalytic hydrogenation?
Aldehydes form primary alcohols, and ketones form secondary alcohols.
Which reagents distinguish Clemmensen reduction from Wolff–Kishner reduction?
Clemmensen uses zinc amalgam and concentrated hydrochloric acid; Wolff–Kishner uses hydrazine, then heating with strong alkali.
What does Wolff–Kishner reduction convert a carbonyl group into?
A methylene group, .
How do common oxidants affect aldehydes and ketones?
Aldehydes readily form carboxylic acids; ketones generally need vigorous oxidation that cleaves carbon–carbon bonds.
Why are aldehyde and ketone alpha hydrogens acidic?
The carbonyl group withdraws electrons, and the conjugate base is resonance-stabilized.
What do aldehydes and ketones with an alpha hydrogen form by base-catalysed aldol addition?
Beta-hydroxy carbonyl compounds.
What can beta-hydroxy carbonyl compounds form by losing water?
Alpha,beta-unsaturated carbonyl compounds.
What reaction do aldehydes without an alpha hydrogen undergo with concentrated alkali?
The Cannizzaro reaction.
What happens to the two aldehyde molecules in the Cannizzaro reaction?
One is reduced to an alcohol, while the other is oxidised to a carboxylate.
What functional group defines carboxylic acids?
The carboxyl group, –COOH.
What determines whether a carboxylic acid is aliphatic or aromatic?
The group attached to its carboxyl carbon.
How are aliphatic carboxylic acids named from their corresponding alkanes?
Replace the alkane’s final -e with -oic acid.
Which number is assigned to the carboxyl carbon in an aliphatic carboxylic acid?
Number one.
Which compounds oxidise to carboxylic acids using suitable oxidising agents?
Primary alcohols and aldehydes.
How do Grignard reagents form carboxylic acids using carbon dioxide?
They react with carbon dioxide, followed by acidification.
How many more carbon atoms do these acids contain than the starting alkyl halides?
One more carbon atom.
How do carboxylic acids’ boiling points compare with those of comparable-mass aldehydes, ketones, and alcohols?
They have higher boiling points.
What causes carboxylic acids’ unusually high boiling points?
Extensive intermolecular hydrogen bonding and dimer formation.
What is the formula for the acidity measure pKa?
What does a smaller pKa indicate about an acid?
A stronger acid.
Why are carboxylic acids stronger than alcohols and simple phenols?
Their carboxylate ion is stabilized by two equivalent resonance structures, delocalizing its negative charge over two oxygen atoms.
How does the carboxylate ion differ from the phenoxide ion in stabilization?
The carboxylate ion is more stabilized by resonance than the phenoxide ion.
How do electron-withdrawing substituents affect carboxylic acid strength?
They increase acid strength by stabilizing the conjugate base.
How do electron-donating substituents affect carboxylic acid strength?
They decrease acid strength by destabilizing the conjugate base.
What is the hybridisation of the carbonyl carbon?
sp2-hybridised.
What geometry describes the carbonyl carbon?
Trigonal coplanar.
What are the approximate bond angles around the carbonyl carbon?
Approximately 120°.
What suffix names an aldehyde group attached to a ring?
Carbaldehyde.
Where does numbering start when a ring bears an aldehyde group?
At the ring carbon attached to the aldehyde group.
How are common aldehyde names generally derived from carboxylic acid names?
Replace -ic acid with aldehyde.
How are common ketone names formed from the groups bonded to the carbonyl?
They identify the two groups bonded to the carbonyl.
What does reductive ozonolysis of alkenes produce, depending on substitution?
Aldehydes, ketones, or both.
What product forms when ethyne is hydrated with sulfuric acid and mercury sulfate?
Ethanal.
What does Rosenmund reduction convert acyl chlorides into?
Aldehydes.
What does Stephen reduction convert nitriles into before hydrolysis?
Imines.
What products can DIBAL-H selectively form from nitriles and esters?
Aldehydes.
What can Etard oxidation of methylbenzenes prepare?
Aromatic aldehydes.
Which reagents enable Gatterman–Koch formylation of benzene?
Carbon monoxide and hydrogen chloride, with anhydrous aluminium chloride or cuprous chloride.
What is the room-temperature physical state of methanal, ethanal, and other aldehydes and ketones?
Methanal is a gas, ethanal is a volatile liquid, and others are liquids or solids.
What do aldehydes and ketones form when they react with hydrogen cyanide?
Cyanohydrins.
How does base catalyse cyanohydrin formation?
It generates the stronger nucleophile, cyanide ion.
For which carbonyl compounds does sodium hydrogensulfite addition generally occur readily?
Most aldehydes.
What does aqueous mineral acid do to acetals and ketals?
It hydrolyses them back to carbonyl compounds.
What do ammonia and its derivatives form with aldehydes and ketones after dehydration?
C=N derivatives.
What visible result does Tollens’ reagent produce with aldehydes?
A bright silver mirror forms as the aldehyde is oxidised to a carboxylate.
Which aldehydes produce a reddish-brown precipitate with Fehling’s reagent?
Aliphatic aldehydes.
What products form when methyl ketones react with sodium hypohalite?
Haloform and a carboxylate with one fewer carbon atom.
Which groups does the iodoform reaction detect?
groups or groups that oxidise to .
How many products can form in a crossed aldol condensation of two carbonyl compounds with alpha hydrogens?
Four products.
Where do aromatic aldehyde and ketone carbonyl groups direct electrophilic substitution?
To the meta position.
How do carbonyl groups affect the reactivity of aromatic rings?
They deactivate the ring.
What concentration of formaldehyde solution is used to preserve biological specimens?
A 40% formalin solution.
Which materials are manufactured using formaldehyde?
Bakelite and urea-formaldehyde glues.
Which products are manufactured using acetaldehyde?
Acetic acid, ethyl acetate, vinyl acetate, polymers, and drugs.
In which industries is benzaldehyde used?
Perfumery and dye industries.
What is the common industrial use of acetone and ethyl methyl ketone?
They are common industrial solvents.
How are compounds with multiple carboxyl groups named?
With terms such as dicarboxylic acid or tricarboxylic acid.
How are carboxyl-group positions shown in compounds with multiple carboxyl groups?
By numerals.
How many carbon atoms do fatty acids typically contain?
12–18 carbon atoms.
In what form do fatty acids occur in natural fats?
As glycerol esters.
What does vigorous oxidation do to primary and secondary alkyl groups on aromatic rings?
It converts them to carboxyl groups.
What happens to tertiary alkyl groups on aromatic rings during vigorous oxidation?
They remain unaffected.
What do acidic or basic hydrolysis of nitriles and amides produce?
Carboxylic acids.
What can mild nitrile hydrolysis stop at?
The amide stage.
Which compounds produce carboxylic acids by hydrolysis?
Acyl halides, anhydrides, and esters.
What is the room-temperature physical state of aliphatic carboxylic acids with up to nine carbon atoms?
They are colourless liquids.
What is the physical state of higher aliphatic carboxylic acids at room temperature?
They are wax-like solids.
Which carboxylic acids are miscible with water?
Those with up to four carbon atoms.
How does carboxylic acid solubility in water change as the carbon chain grows?
It decreases, and higher acids are practically insoluble.
What are the pKa values of trifluoroacetic, benzoic, and acetic acids, respectively?
0.23, 4.19, and 4.76.
What is the increasing acidity order of the listed substituents?
Ph < I < Br < Cl < F < CN < NO2 < CF3.
Answer 32 questions on Aldehydes Ketones and Carboxylic Acids.
1. Which structural feature defines a carbonyl group?
2. A compound has a carbonyl carbon bonded to one carbon atom and one hydrogen atom. How is the compound classified?
Go over the full study guide for Aldehydes Ketones and Carboxylic Acids.
Read the study guide →Upload your class notes and Revizly writes your flashcards in about a minute.
Flashcard maker