What functional group is present in both aldehydes and ketones?
Carbonyl
The carbonyl group consists of a C=O double bond.
What type of species commonly attacks the carbonyl carbon in aldehydes and ketones?
Nucleophile
The carbonyl carbon is partially positive and susceptible to nucleophilic attack.
Fill in the blank:
The carbon atom in the carbonyl group has a partial _______ charge.
positive
The electronegative oxygen pulls electron density away from carbon.
True or False:
Aldehydes are more easily oxidised than ketones.
True
Aldehydes oxidise readily to form carboxylic acids.
What oxidising reagent produces a silver mirror with aldehydes?
Tollens’ reagent
Aldehydes reduce Ag+ ions to metallic silver.
True or False:
Ketones give a positive result with Fehling’s solution.
False
Only aldehydes reduce Fehling’s solution to form a brick red precipitate.
Fill in the blank:
Reduction of an aldehyde forms a _______ alcohol.
primary
The carbonyl group is reduced to a hydroxyl group.
What type of alcohol is formed when a ketone is reduced?
Secondary alcohol
The carbonyl carbon becomes bonded to an –OH group.
True or False:
Aqueous Sodium borohydride (NaBH4) is used as a reducing agent for aldehydes and ketones.
True
It supplies hydride ions for nucleophilic addition.
Fill in the blank:
In NaBH4 reductions, the nucleophile that attacks the carbonyl carbon is _______.
H-
The hydride ion adds to the carbonyl carbon.
What product forms when aldehydes or ketones react with HCN?
Hydroxynitrile
The CN- ion adds to the carbonyl carbon followed by protonation.
Why can hydroxynitrile formation from aldehydes produce a mixture of enantiomers?
Planar carbonyl group
Nucleophiles can attack from either side of the carbonyl plane.
Name the mechanism for the reduction of aldehydes and ketones to alcohols.
Nucleophilic addition
Name the mechanism for the reaction of aldehydes and ketones with KCN.
Nucleophilic additon
What are the conditions required for the nucleophilic addition of aldehydes and Ketones with KCN?
KCN followed by dilute acid
What is the main hazard of potassium cyanide (KCN)?
It is toxic
What is the general reduction equation for an aldehyde?
RCHO + [H] → RCH₂OH
What is the general reduction equation for a ketone?
R₁COR₂ + [H] → R₁CHOHR₂
What is the general equation for formation of a hydroxynitrile from an aldehyde?
RCHO + HCN → RCH(OH)CN
What is the general equation for formation of a hydroxynitrile from a ketone?
R₁COR₂ + HCN → R₁C(OH)(CN)R₂
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2.1 Atoms, Compounds, Molecules & Equations50
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2.2 Amount of Substance47
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2.3 Acid–Base69
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2.4 Electrons, Bonding and Structure90
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3.1 Periodicity22
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3.2 Group 2 and Halogens55
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3.3 Qualitative Analysis39
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3.4 Enthalpy Changes62
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3.5 Reaction Rates (Qualitative)55
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3.6 Equilibrium (Qualitative)24
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4.1 Basic Organic Chemistry Concepts42
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4.2 Hydrocarbons85
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4.3 Alcohols and Haloalkanes79
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4.4 Organic Synthesis12
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4.5 Analytical Techniques (IR & MS)36
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5.1 Reaction Rates (Quantitative)24
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5.2 Equilibrium (Quantitative)12
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5.3 pH and Buffers15
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5.4 Enthalpy, Entropy & Free Energy27
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5.5 Redox & Electrode Potentials63
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5.6 Transition Elements95
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6.1 Aromatic Compounds29
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6.2 Carbonyl Compounds20
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6.3 Carboxylic Acids & Esters25
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6.4 Nitrogen Compounds102
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6.5 Polymers24
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6.6 Organic Synthesis (Advanced)20
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6.7 Chromatography & Spectroscopy (NMR)26
