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NEET Chemistry MCQ
Aldehydes, Ketones Mcq Neet Chemistry
Quiz 8
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Q.1
A substance C4H10O yields on oxidation compound C4H8O which gives an oxime and a positive iodoform test. The original substance on treatment with conc. H2SO4 gives C4HThe structure of the compound is
0%
a) CH3CH2 - O - CH2CH3
0%
b) (CH3)3COH
0%
c) CH3CH(OH)CH2CH3
0%
d) CH3CH2CH2CH2OH
Explanation
2-Butanon forms oxime on reaction with hydroxylamine (NH2OH) and also gives positive iodoform test Answer : (c)
Q.2
han One Correct Answer Q212) Which will react with acetone to give a product containing >C=N, linkage?
0%
a) (CH3)3N
0%
b) C6H5NHNH2
0%
c) NH2CONHNH2
0%
d) C6H5NHC6H5
Explanation
Answer : (b,c )
Q.3
The reagent with which both aldehydes and ketones react is ... ... [ IIT 1981]
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a) Gehling solution
0%
b) Grignard's reagent
0%
c) Schiff's reagent
0%
d) Tollen's reagent
Explanation
Both aldehyde nad ketones reats with Grignard's reagent to yield alcohol Answer : (b)
Q.4
Silver mirror is a test for
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a) Aldehyde
0%
b) Thioalcohols
0%
c) Acids
0%
d) Ethar
Explanation
Answer : (a)
Q.5
C6H5CHO + HCN → C6H5CH(CN)OH. The product would be
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a) meso compound
0%
b) optically active
0%
c) racemate
0%
d) mixture of diastereomers
Explanation
Since the cyanohydrin produced is a chiral compound, it is optically active, we obtain both enantiomeric forms of the product. Thus product as a whole would be racemic mixture Answer : (c)
Q.6
Formaldehyde can be distinguished from acetaldehyde by
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a) Ammoniacal AgNO3
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b) Ammonia
0%
c) Fehling's solution
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d) Schiff's reagent
Explanation
Formaldehyde and acetaldehyde react to different manner towards NH3 6HCHO + 4NH3 → (CH2)6N4 CH3CHO + NH3 → CH3CH(OH)NH2 Answer : (b)
Q.7
han One Correct Answers Q217) Which is/are isomer(s)?
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a) Propionic acid and ethyl acetate
0%
b) Propionaldehyde and acetone
0%
c) Urea and ammonium cyanate
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d) Xylenes
Explanation
Answer : (a,c,d)
Q.8
Catalyst SnCl2/HCl is used in
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a) Cannizzaro reaction
0%
b) Clemmensen reduction
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c) Rosenmnd's reaction
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d) Stephen's reaction
Explanation
Answer : (d)
Q.9
Between p-nitrophenol and salicylaldehyde, solubility in base is
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a) equal in nature
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b) higher for salicylaldehyde
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c) almost nil in both cases
0%
d) higher in p-nitrophenol
Explanation
Due to acidic nature Answer : (d)
Q.10
At room temperature formaldehyde is
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a) liquid
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b) solid
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c) gas
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d) none of these
Explanation
Answer : (c)
Q.11
on Q221) The appropriate reagent for transformation
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a) Zn(Hg), HCl
0%
b) NH2NH2, OH-
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c) H2/Ni
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d) NaBH4
Explanation
- COCH3 group can be reduced to - CH2CH3 by either Zn-Hg, HCl or NH2NH2, OH- but with Zn-Hg, HCl, dehydration of lacohol takes place by HCl. SO NH2NH2, OH- is better reagent Answer : (b)
Q.12
Ketones are less reactive than aldehydes because
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a) of electromeric effect
0%
b) of steric hindrance to the attacking reagent
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c) C=O group is less polar in ketones
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d) none of the above
Explanation
Answer : (b)
Q.13
Pinacole is
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a) 3-methyl butan-2-ol
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b) 2,3-dimethyl-2,3-butandiol
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c) 3,3-dimethyl-2-propanone
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d) none of the above
Explanation
Answer : (b)
Q.14
Fehling solution is a mixture of two solutions. While one solution contains CuSO4, the other contains
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
Answer : (a)
Q.15
on Q225) The above reaction is known as
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a) Beckmann rearrangement
0%
b) Benzilic acid rearangement
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c) Benzoin condensation
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d) Aldol condensation
Explanation
Benzilic acid rearrangement Answer : (b)
Q.16
han One Correct Answer Q226) Which of the following do not undergo base-catalysed aldol condensation?
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a) p-methylbenzaldehyde
0%
b) 2-methylpropionaldehyde
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c) 2,2-dimethylpropionaldehyde
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d) Benzaldehyde
Explanation
Answer : (a,c,d)
Q.17
Which of the following products is formed when benzaldhyde is treated with CH3MgBr and the addition product so obtained is subjected to acid hydrolysis? ... ..[ HArryana EET 2000 ]
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a) Secondary alcohol
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b) Primary alcohol
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c) phenol
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d) tert- butyl alcohol
Explanation
Answer : (a)
Q.18
The reagent(s) which can be used to distinguish acetophenone from benzophenone is (are)
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a) Aqueous solution of NaHSO3
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b) Benedict reagent
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c) 2, 4 -dinitrophenyl hydrazine
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d) I2 and Na2CO3
Explanation
Acetophenone forms Iodoform For Benzophenone , no iodoform formation Answer : (d)
Q.19
Paraldehyde is used as a
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a) saporific
0%
b) poison
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c) polymer
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d) dye
Explanation
Paralehyde is sued as hynotic and sprorific ( sleep producing) drug Answer : (a)
Q.20
Which of the following alcohol cannot be produced by treatment of aldehydes or ketones with NaBH4 or LiAlH4? [ Punjab CET 1990]
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a) 1_propanol
0%
b) 2-Propanol
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c) 2-Methyl-2-Propanol
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d) Ethanol
Explanation
Tertiary alcohols can not be produced by reduction of aldehydes and ketones Answer : (c)
Q.21
on Q231) Predict the product 'B' in the sequence of reaction
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a) CH3COOH
0%
b) CH3CHO
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c) CH3COONa
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d) CH3CH(OH)CH2CHO
Explanation
Answer : (d)
Q.22
Paraldehyde is
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a) a trimer of formaldehyde
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b) a trimer of acetaldehyde
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c) a hexamer of formaldehyde
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d) a hexamer of acetaldehyde
Explanation
Answer : (b)
Q.23
han One Correct Answer Q233) The silver mirror with Tollens reagent is formed by
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a) acetone
0%
b) ethanal
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c) ethyl acetate
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d) glucose
Explanation
Answer : (b,d)
Q.24
Partial oxidation of methane gives
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a) HCOOH
0%
b) H2O and CO2
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c) HCHO
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d) CO and H2O
Explanation
Answer : (d)
Q.25
Cyanohydrin of which of the following forms lactic acid?
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a) CH3CH2CHO
0%
b) CH3CHO
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c) CH3COCH3
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d) HCHO
Explanation
Answer : (b)
Q.26
The increasing order of the rate of HCN addition to compounds A to D is A) HCHO B) CH3COCH3 C) PhCOCH3 D) PhCOPh ... ...[ AIEEE 2006]
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a) A < B < C < D
0%
b) D < B < C < A
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c) D < C < B < A
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d) C < D < B < A
Explanation
Addition of HCN to carbonyl compounds is an example of nucleophilic addition reaction of carbonyl compounds. Order of reactivity of carbonyl compounds to wards nucleophilic addition reaction is The aromatic aldehydes and ketones are less reactive than their aliphatic analogous. This is due to the +R effect of the benzene ring Answer : (c)
Q.27
Aliphatic aldehydes react with Fehling's solution to give red ppt. but benzaldehyde does not produce red ppt with Fehling's solution because
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a) of bulky ring, -CHO is hinderer
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b) of resonance, oxidation of benzaldehyde is difficult
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c) - CHO is present in cyclic structure
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d) of all the above
Explanation
Resonance give stability Answer : (b)
Q.28
on Q238) the product X is
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a) CH3OH + CH3OH
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b) CH2OH - COO-
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c) CH3OH + HCOOH
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d) OOC - COO-
Explanation
This is internal Cannizzaro's reaction Answer : (b)
Q.29
The decreasing order of solubility of methanal (A), propanaldehyde (B), benzaldehyde (C) and acetophenone (D)
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a) A > B > C > D
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b) D > C > D > A
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c) D > A > B > C
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d) B > A > C > D
Explanation
Solubility of organic compounds in water decreases with molar due to increaseing hydrophobic character of alkyl or aryl group Answer : (a)
Q.30
Propanal on treatment with dilute sodium hydroxide forms
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a) CH3CH2COONa
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b) CH3CH2CH2CH2CH2CHO
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c) CH3CH2CH(OH)CH(CH3)CHO
0%
d) CH3CH2CH(OH)CH2CH2CHO
Explanation
Aldol Condensation Answer : (c)
0 h : 0 m : 1 s
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