Chapter 26 Flashcards
What carbonyl functional group do both aldhydes and ketones contain?
C=O
In aldehydes, where is the carbonyl functional group found?
At the end of a carbon chain
In its structural formula, what is the aldehyde group written as?
CHO
In its structural formula, what is the ketone group written as?
CO
What is the name of the simplest aldehyde?
methanal
What is the structure of the simplest aldehyde?
HCHO
What is the name of the simplest ketone?
propanone
What is the structure of the simplest ketone?
CH₃COCH₃
What is the common name for propanone?
acetone
What is the common name for methanal?
formaldehyde
What is formaldehyde used for?
To preserve biological specimens
How do you represent an oxidising agent?
[O]
What are aldehydes oxidised to?
Carboxylic acids
What are the conditions needed to oxidise aldehydes?
1) reflux
2) acidified dichromate(VI) ions, Cr₂O₇²⁻/H⁺
- -> sodium or potassium dichromate(VI), K₂Cr₂O₇
- -> dilute sulfuric acid, H₂SO₄
Can ketones be oxidised?
No
Can aldehydes be oxidised?
Yes
What influences the reactivity of aldehydes + ketones?
The nature of the carbon-oxygen double bond?
What is the carbon-hydrogen double bond made up of?
1) σ-bond
2) π-bond
Is the C=C double bond in alkenes polar or non-polar?
non-polar
Is the C=O double bond in carbonyl compounds polar or non-polar?
polar
Why is the C=O double bond polar?
1) oxygen is more electronegative than carbon
2) electron density in the double bond lies closer to the oxygen atom
3) carbon end of the bond is more positive
3) oxygen end of the bond more negative
What type of reactions do aldehydes + ketones undergo?
nucleophilic addition
What type of reactions do alkenes undergo?
electrophilic addition
What is a nucleophile?
An atom (or group of atoms) which is attracted to an electron-defficient centre or atom, where it donates a pair of electrons to form a new covalent bond
What is a σ-bond?
A bond formed by the overlap of one orbital from each bonding atom, consisting of two electrons and with the electron density centred around a line directly between the nuclei of the two atoms
What is a π-bond?
A bond formed above and below the plane of the carbon and oxygen atoms, formed by the sideways overlap of p-orbitals
What is the reducing agent used to reduce aldehydes and ketones to alcohols?
sodium tetrahydridoborate(III), NaBH₄
What type of alcohols are aldehydes reduced to?
Primary alcohols
How do you represent the reducing agent in the reduction of organic compounds?
[H]
What type of alcohols are ketones reduced to?
Secondary alcohols
What type of reaction is carbonyl compounds with HCN?
addition reaction