aldehydes and ketones

Question 1

the general formula of carbonyls

Answer 1

CnH2nO

Question 2

conditions for the preparation of formaldehyde by laboratory method

Answer 2

300 degrees celsius
Pt asbestos
or Ag or Cu

Question 3

composition of formalin

Answer 3

formaldehyde 40%
water 52%
unreacted methanol 8%

Question 4

using laboratory method formaldehyde can be prepare by

Answer 4

methanol

Question 5

conditions to prepare formaldehyde using industrial method

Answer 5

500 degrees Celsius
FeO2 Mo2O3
or Ag

Question 6

conditions for acetaldehyde preparation using laboratory method

Answer 6

Na2Cr2O7
Conc. H2SO4

Question 7

why acetaldehyde is immediately distilled during its preparation by using laboratory method

Answer 7

to avoid its further oxidation which can convert it into carboxylic acid

Question 8

conditions for the preparation of acetaldehyde using industrial method

Answer 8

PdCl2 as catalyst
CuCl2 as promoter

Question 9

dry distillation of calcium formate form

Answer 9

formaldehyde

Question 10

dry distillation of calcium acetate form

Answer 10

acetone

Question 11

dry distillation of a mixture of calcium formate and calcium acetate form

Answer 11

Acetaldehyde / formaldehyde/ acetone

Question 12

during dry distillation of a mixture of calcium acetate and calcium, the interaction between two acetates form

Answer 12

acetone

Question 13

during dry distillation of a mixture of calcium acetate and calcium, the interaction between two formates form

Answer 13

formaldehyde

Question 14

most of the reagents add to carbonyl group by _______ reaction

Answer 14

addition

Question 15

polarity of carbonyl group is due to

Answer 15

the oxygen atom of carbonyl group being electronegative attracts the pi electrons towards itself making the group polar

Question 16

the electronic configuration around the carbonyl group is

Answer 16

unsymmertrical

Question 17

most of the reactions of carbonyl group is considered to be _______ addition

Answer 17

neucleophilic

Question 18

the initial attack of nucleophile is on ___ of carbonyl compound

Answer 18

carbon

Question 19

what is the difference in the adducts formed in acid and base-catalyzed reaction

Answer 19

whether the addition is acid catalyzed or base catalyzed the adduct is the same

Question 20

how a base catalyze the nucleophilic addition reaction of carbonyl compounds

Answer 20

it increases the nucleophilic character of nucleophile

Question 21

how an acid catalyzes the nucleophilic addition reaction of carbonyl compounds

Answer 21

it increases the electrophilic character of carbonyl carbon

Question 22

hydrogen cyanide adds to aldehydes and ketones to form

Answer 22

cyanohydrins

Question 23

the cyanogroup of cyanohydrin is hydrolyzed by an aqueous acid into a

Answer 23

carboxylic acid

Question 24

acetaldehyde cyanohydrin is hydrolyzed to give

Answer 24

lactic acid

Question 25

the reation in which cyanohydrins of carbonyl compounds are hydrolyzed is used to synthesize

Answer 25

alpha hydroxy acids

Question 26

alpha hydroxy acids formed by the hydrolysis of cyanohydrins have carbon atoms

Answer 26

one more carbon atom than the no of carbon atoms in the starting aldehydes and ketones

Question 27

nucleophilicity of hydrogen cyanide

Answer 27

hydrogen cyanide itself is not very nucleophilic and does not ionize to form cyanide ions to a significant extent. Thus a source of cyanide ions such as KCN or NaCN is used

Question 28

reaction of Grignard reagent with a carbonyl compound

Answer 28

grignard reagents react with aldehydes and ketones to give adducts which on hydrolysis with dilute mineral acids give alcohols

Question 29

which ketones react with sodium bisulphite

Answer 29

methyl ketones

Question 30

aldehydes and methyl ketones react with a saturated solution of sodium bisulphite to form a ___________ adduct

Answer 30

crystalline white precipitates of sodium bisulphite

Question 31

the reaction of carbonyl compounds with sodium bisulphite is used for

Answer 31

separation and purification of carbonyl compounds from non carbonyl compounds

Question 32

in addition product of sodium bisuphite the carbon atom is bonded to suphure due to

Answer 32

because sulphur is more nucleophilic than oxygen

Question 33

which aldehydes and ketones are used in aldol condensation

Answer 33

aldehydes and ketones possessing alpha hydrogen

Question 34

during aldol condensation the aldehydes and ketones react with

Answer 34

cold dilute solution of an alkali

Question 35

the name aldol is given due

Answer 35

the product contain both aldehyde and alcohol group

Question 36

the name aldol condensation is reserved for

Answer 36

reactions that start with two identical carbonyl compounds

Question 37

the aldol compound readily loses water on heating in the presence of dilute acid to give

Answer 37

unsaturated carbonyl compound

Question 38

the nucleophile in aldol condensation reaction is

Answer 38

carbanion

Question 39

which aldehydes undergo cannizarro reaction

Answer 39

aldehydes having no alpha hydrogen

Question 40

cannizarro reaction is a _________ reaction

Answer 40

disproportionation reaction

Question 41

during cannizarro reaction the molecule of aldehyde which is being converted into alcohal is

Answer 41

reduced

Question 42

during cannizarro reaction the aldehyde molecule which is being converted into acid is

Answer 42

oxidized

Question 43

the cannizarro reaction is carried out in the presence of

Answer 43

50 percent sodium hydroxide

Question 44

the nucleophile in cannizarro reaction is

Answer 44

hydroxide ion

Question 45

which carbonyl compounds undergo haloform reactio

Answer 45

only acetaldehyde and methyl ketones

Question 46

which alcohols give haloform reaction

Answer 46

secondary alcohols and ethanol is only primary alcohol that gives haloform reaction

Question 47

which primary alcohol gives haloform reaction

Answer 47

ethanol

Question 48

haloform reaction is used to convert methyl ketone to

Answer 48

carboxylic acids

Question 49

the carboxylic acids formed by the haloform reaction contain carbon atoms

Answer 49

one less than the parent comound

Question 50

idofrom is

Answer 50

insoluble yellow solid

Question 51

uses of idoform test

Answer 51

to distinguish methyl ketones from other ketones ethanol from methanol and other primary alcohols acetaldehydes from other aldehydes