Aldehydes and Ketones Flashcards

1
Q

what is a carbonyl group?

A

C=O

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2
Q

what is the functional group and general formula for and aldehyde?

A

RCHO( C double bonded to O, single bond to H and R )

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3
Q

what is the functional group for a ketone?

A

RCOR’ ( C double bonded to O )

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4
Q

how do you name aldehydes?

A

-al suffix

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5
Q

how do you name ketones?

A

-one suffix

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6
Q

what kind of intermolecular forces do molecules with the carbonyl group have? why?

A

Permanent dipole-dipole due to the polar C=O bond

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7
Q

are they soluble are they in water? what influences solubility?

A

Yes- because they can form hydrogen bonds between water molecules and oxygen of C=O. as the carbon chain length increases the solubility decreases.

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8
Q

what bond in carbonyl compounds is usually involved in reactions? why?

A

C=O due to the polarity of the bond ( large difference in electronegativity between carbon and oxygen )

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9
Q

why is the addition of HCN important?

A

increases the length of the carbon chain by one carbon atom- very useful

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10
Q

will the product of HCN added to a carbonyl compound have optical isomers? why?

A

yes they will. in the aldehyde/ketone, the carbonyl group is planar, so the :CN- can attack from either above or below, forming two enantiomers

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11
Q

what is the name of the product when HCN is added to a carbonyl compound?

A

Hydroxynitriles

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12
Q

what is Fehlings solution? what colour is it?

A

Copper complex ions, blue

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13
Q

what happens when an aldehyde is added to Fehlings solution?

A

reduced to C+ ions –> colour change to brick red ppt

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14
Q

what happens when a ketone is added to Fehlings solution?

A

no visible change –.> stays blue

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15
Q

what is tollens reagent?

A

silver complex ions, colourless solution

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16
Q

what happens when an aldehyde is added to tollens reagent?

A

silver mirror forms as Ag+ is reduced to Ag

17
Q

what happens when an ketone is added to tollens reagent?

A

no visible change

18
Q

what is another oxidising agent for alcohols and aldehydes? what change in colour does this undergo?

A

acidified potassium dichromate (VI) H2SO4 and K2Cr2O7. colour change from orange to green

19
Q

what is a reducing agent for aldehydes and ketones? what ions does this release in solution?

A

NaBH4
releases an H- ion

20
Q

write an equation for the reduction of pentan-2-one

A

CH3COHCH2CH2CH3 + [H] —> CH3CH(OH)CH2CH2CH3