Carbonyl Compounds Flashcards
Why do aldehydes and ketones have higher boiling points than alkanes with the same number of carbon atoms?
The carbonyl bond means that there are permanent dipole dipole interactions between the molecules which are not present between the alkane molecule
Why do aldehydes and ketones have lower boiling points than alcohols with the same number of carbon atoms?
There is hydrogen bonding between the alcohol molecules. This is a stronger intermolecular force than the dipole dipole attractions between the carbonyl compounds
Why are small carbonyl compounds miscible in water?
The formation of hydrogen bonds from the water to the oxygen of the carbonyl compound.
Why is the carbonyl bond polar?
The difference in electronegativity between carbon and oxygen
What is the difference in structure between an aldehyde and ketone?
“ALDEHYDES have at least one H attached to the carbonyl group. Ketones have two carbons attached to the carbonyl group.
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Name this molecule CH3CH2COCH2CH3
“pentan-3-one
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Explain in detail the technique recrystallization.
Dissolve the solute in the minimum volume of hot solvent, cool the solution to allow the crystals to form, remove the crystals by vacuum filtration, dry the resulting crystals in an oven.
What measurement of a substance is the best measure of its purity
Melting Point
Give the name of a suitable reducing agent for the reduction of a carbonyl compound to an alcohol.
Lithium Tetrahyridoaluminate, Sodium Tetrahydridoborate
What is the nucleophile produced by NaBH4 and LiAlH4?
H-
“Why is Propanoyl chloride more easily reduced by Hydride ions than Propanal.
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“Chlorine are more electronegative than carbon, Atoms attached to the carbonyl carbon that are more electronegative than carbon make it more delta positive (1)
More delta positive the carbonyl carbon is the more reactive it is, towards nucleophiles such as H-, Therefore carbonyl carbon is most delta positive in propanoyl chloride (1) and propanoyl chloride is the most reactive with H-.
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What are the reagents for the nucleophilic addition of cyanide ions to aldehydes or ketone?
“hydrogen cyanide - HCN in the presence of KCN
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What are the conditions for the nucleophilic addition of cyanide ions to aldehydes or ketone?
“reflux in alkaline solution
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What is the structural formula of the product of the reaction of these two molecules CH3CHO + HCN
“CH3CH(OH)CN
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