Chapter 26.1

Question 1

carbonyl definition

Answer 1

Carbonyls are compounds with a C=O bond.
They can be either aldehydes or ketones

Question 2

If the C=O is on the end of the
chain with an H attached it is an

Answer 2

aldehyde

Question 3

aldehyde ending and functional group

Answer 3

-al
CHO

Question 4

If the C=O is in the middle of
the chain it is a

Answer 4

ketone

Question 5

ketone ending and functional group

Answer 5

-one
-CO

Question 6

carbonyl solubility in water

Answer 6

the smaller carbonyls are soluble in water because they can form hydrogen bonds with water.

Question 7

Pure carbonyls cannot hydrogen bond, but
bond instead by

Answer 7

permanent dipole forces

Question 8

In comparison to the C=C bond in alkenes, the C=O is stronger and does not

Answer 8

undergo addition reactions easily.

Question 8

The C=O bond is polarised because

Answer 8

O is more electronegative than
carbon. The positive carbon atom attracts nucleophiles

Question 9

potassium dichromate reaction with primary alcohols

Answer 9

primary alcohol-> aldehydes DISTIL
aldehyde-> carboxylic acids UNDER REFLUX

Question 10

potassium dichromate reaction with secondary alcohol

Answer 10

secondary alcohol-> ketone under REFLUX
no further oxidation

Question 11

equation for aldehyde oxidation

Answer 11

RCHO + [O] -> RCOOH

Question 12

observation of potassium dichromate reaction

Answer 12

Observation: the orange dichromate ion (Cr2O72-) reduces to the green Cr 3+ ion

Question 13

aldehyde with tollens reagent reagent, conditions and observation

Answer 13

Reagent: formed by mixing aqueous ammonia and silver
nitrate. active substance is the complex ion of [Ag(NH3)2]+

Conditions: heat gently

Observation: with aldehydes, a silver mirror forms. Ketones result in no change as no further oxidation

Question 14

aldehyde with tollens reagent reaction

Answer 14

Reaction: aldehydes only are oxidised by Tollens’ reagent into a carboxylic acid. The silver(I) ions are reduced to silver atoms.

Question 15

aldehyde with tollens reagent equation

Answer 15

CH3CHO + 2Ag+ + H2O-> CH3COOH + 2Ag + 2H+

Question 16

reducing agents such as … will reduce carbonyls
to alcohols

Answer 16

Reducing agents such as NaBH4
(sodium tetrahydridoborate)

Question 17

aldehyde and ketone reduced to what kind of alcohols

Answer 17

aldehydes-primary alcohols
ketones-secondary alcohols

Question 18

nucleophilic addition for aldehydes/ketones

Answer 18

nabh4 has a source of h- attracted to carbon in c=o bond
water is added

Question 19

Catalytic Hydrogenation-
Reagent:
Conditions:

Answer 19

Catalytic Hydrogenation-
Reagent: hydrogen and nickel catalyst
Conditions: high pressure

Question 20

Addition of hydrogen cyanide to carbonyls to form hydroxynitriles
reagent,conditions and mechanism

Answer 20

Reagent: sodium cyanide (NaCN) and dilute sulfuric
acid.
Conditions: Room temperature and pressure
Mechanism: nucleophilic addition

Question 21

in hydroxynitrile formation, The NaCN supplies the
nucleophilic—
The H2SO4 acid supplies the — needed in second step of the
mechanism

Answer 21

in hydroxynitrile formation, The NaCN supplies the
nucleophilic CN- ions.
H2SO4 acid supplies H+ ions needed in second step of the
mechanism

Question 22

testing for carbonyls

Answer 22

2,4-DNP reacts with both aldehydes and ketones. The
product is an orange precipitate

Question 23

to identify the carbonyl used after 2,4-DNP

Answer 23

tollens reagent to identify aldehyde THEN
The melting point of the crystal formed can be used to find specific, compare with data