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NEET Chemistry MCQ
Aldehydes, Ketones Mcq Neet Chemistry
Quiz 1
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Q.1
Chlorine does not react with
0%
a) CH3CHO
0%
b) C6H5CHO
0%
c) propanone
0%
d) methanal
Explanation
Answer : (d)
Q.2
Base catalysed aldol condensation occurs with
0%
a) propionaldehyde
0%
b) 2,2-dimethyl propionaldehyde
0%
c) benzaldehyde
0%
d) none of the above
Explanation
Aldol condensation takes place in aldehyde having α-H atom Answer : (a)
Q.3
Reaction between benzaldehyde and acetophenone in presence of dilute NaOH is known as ... [NEET 2020]
0%
a) Cross Cannizzaro’s reaction
0%
b) Cross Aldol condensation
0%
c) Aldol condensation
0%
d) Cannizzaro’s reaction
Explanation
Answer: (b)
Q.4
tion Q2) Identify compound X in the following sequence of reactions ... [NEET 2020]
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
Answer: (a)
Q.5
X heated with soda lime and gives ethane. X is ... [ AFMC 2005]
0%
a) ethanoic acid
0%
b) methanoic acid
0%
c) propionic acid
0%
d) ether
Explanation
CH3CH2COOH → CH3CH3 + CO2 ↑ ( inpresence of NaOH + CaO) Answer:(c)
Q.6
Which of the following us correct order of acidity? [ AFMC 2011]
0%
a) HCOOH > CH3COOH > ClCH2COOH > C2H5COOH
0%
b) ClCH2COOH > HCOOH >CH3COOH >C2H5COOH
0%
c) CH3COOH > HCOOH > ClCH2COOH > C2H5COOH
0%
d) C2H5COOH > CH3COOH > HCOOH > ClCH2COOH
Explanation
note presence of electron-withdrawing group increases the acidity, while electron releasing group decreases acidity of carboxylic acid Answer: (b)
Q.7
When acetamide reacts with Br2 in presence of NaOH, there is formation of .. [ AFMC 2010]
0%
a) CH3NH2
0%
b) CH3CH2OH
0%
c) CH3CN
0%
d) CH3CHO
Explanation
CH3CONH2 + Br2 + 2NaOH → CH3NH2 +Na2CO3 + 2NaBr + 2H2O This reaction is known as Hoffmann Bromamide reaction Answer: (a)
Q.8
Which of the following does not give benzoic acid on hydrolysis? [ AFMC 2008]
0%
a) Phenyl Cyanide
0%
b) Benzoyl Chloride
0%
c) Benzyl chloride
0%
d) Methyl benzoate
Explanation
Answer: (c)
Q.9
The reagent which does not give acid chloride on treating with carboxylic acid is ... [ AFMC 2007]
0%
a) PCl5
0%
b) Cl2
0%
c) SOCl2
0%
d) PCl3
Explanation
Cl2 does not give acid chloride on treating it with carboxylic acid While PCl3, PCl5 and SOCl2 gives nucleophilic substitution reaction with carboxylic acid , Cl- replaces OH- group of -COOH Answer:(b)
Q.10
By which reaction a ketone can be converted into hydrocarbon? [ AFMC 1999]
0%
a) Aldol condensation
0%
b) Reimer -Tiemann reaction
0%
c) Cannizaro reaction
0%
d) Wilf-Kishner reaction
Explanation
Wolf-Kishner reaction : By this method , carbonyl group is converted to methylene group. Ketone and Aldehydes can be easily reduced to hydrocarbons by this method. Answer: (d)
Q.11
Which of the following can not be used in Friedel-craft's reaction...[ AFMC 204]
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a) FeCl3
0%
b) FeBr3
0%
c) AlCl3
0%
d) NaCl
Explanation
In Friedel-Craft's reaction, lewis acids( electron deficient species) like FeCl3 etc can be used for formation of electrophile and the reaction is given by aromatic compounds( electrophilic substitution) Answer: (d)
Q.12
When dihydroxyacetone reacts with HIO4, the product is /are... [ AFMC 2006]
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a) HCHO
0%
b) HCOOH
0%
c) HCHO and HCOOH
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d) HCHO and CO2
Explanation
Answer: (d)
Q.13
Acetaldehyde reacts with NH3 to form... [ AFMC 2010]
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a) An acidic solution
0%
b) A basic solution
0%
c) A neutral solution
0%
d) Urotropine
Explanation
CH3CHO + NH3 → CH3CH=NH imine formed is basic in nature Answer:(b)
Q.14
Acetone mixed with bleaching powder give .. [ AFMC 2004]
0%
a) Chloroform
0%
b) acetaldehyde
0%
c) ethanol
0%
d) phosgen
Explanation
CaOCl2 + H2O → Ca( OH) 2 + Cl2 Cl2 + H2O → 2HCl + [O] CH3COH3 + Cl2 → CCl3COCH3 CCl3COCH3 + ca(OH)2 → CHCl3 Answer: (a)
Q.15
Reactivity towards nucleophilic addition reaction of (I) HCHO ; (II) CH3CHO ; (III) CH3COCH3 is ... ...[ Orissa JEE 2004]
0%
a) II > III > I
0%
b) III > II > I
0%
c) I > II > III
0%
d) I > II > III
Explanation
Aldehydes are more reactive than ketones towards nucleophilic addition reaction and bulkier than alkyl group attached to carbonyl group lesser is the reactivity. Henece order of reactivity is as per option 'c' Answer : (c)
Q.16
Acetone reacts with Grignard Reagent to form
0%
a) 1° alcohol
0%
b) 2° alcohol
0%
c) 3° alcohol
0%
d) Ether
Explanation
Answer : (c)
Q.17
ion Q15) What is Z in follwing equation
0%
a) Phenyl acetic acid
0%
b) Toluic acid
0%
c) Benzaldehyde
0%
d) Benzoic acid
Explanation
Answer : (c)
Q.18
Than One Correct Answer Q16) The group >CO is present in
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a) aldehydes
0%
b) alcohol
0%
c) ketones
0%
d) ether
Explanation
Answer : (a, c )
Q.19
ion Q17) Assertion: HCHO has sp2-hybridised carbon and the following geometry Reason:The bond angles are changed due to multipe bond-bond pair repulsion
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a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion
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b) The Assertion and Reason are true but Reason is not correct explanation of Assertion
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c) Assertion is true but, Reason is false
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d) Assertion is false but, Reason is true
Explanation
HCHO is sp2 hybridized and geometry structure of trigonal planar. The strucutre composed of 3 sigma bond and one pi bond. The sigma bonds lie on the same plane. Pi bond is formed by sideways overlapping of p orbital of carbon and p orbital of oxygen. Ideally bond angle is usually 120° in trigonal planar. But in formaldehyde ∠HCH = 116° and ∠ HCO = 122° Reason for this distortion is because of the existence of lone pairs of the electrons on the oxygen atom. As we know, the lone pairs are attracted towards the nucleus whereas, the double bonds lead to more repulsion than the single bonds, the bond angles are completely distorted from the ideal percentage of 120° Assertion and reason are true and reason is correct explanation to assertion. Answer : (b)
Q.20
Propyne on hydrolysis in presence of H2SO4 and HgSO4 gives
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a) Acetone
0%
b) Acetadehyde
0%
c) Formaldehyde
0%
d) None
Explanation
Answer : (a)
Q.21
Than One Correct Answer Q19) Which of the following do/does not react with Fehling's solution?
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a) Acetone
0%
b) Acetaldehyde
0%
c) Benzaldehyde
0%
d) Glucose
Explanation
Answer : (a,c)
Q.22
Hybridization of carbon in carbonylic group is
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a) sp
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b) sp2
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c) sp3
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d) none of these
Explanation
Answer : (b)
Q.23
The correct order of reactivity of >CO group in given compounds is
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
Positive IE of alkyl group decreases positive charge on C+ centre of carbonyl group and thus, reactivity order is as option (a) Answer : (a)
Q.24
Than One Correct Answer Q22) Which give(s) nucleophilic acddition reaction(s)?
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a) Ethanal
0%
b) Methanal
0%
c) Propanone
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d) None of these
Explanation
Answer : (a,b,c)
Q.25
Than One Correct Answer Q23) Which of the following undergo(es) Cannizzaro's reaction?
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a) HCHO
0%
b) (CH3)3CCHO
0%
c) CH3CH2CHO
0%
d) CH3CHO
Explanation
Answer : (a,b)
Q.26
In presence of dry HCl gas, CH3CHO condense with C2H5OH to give
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a) aldol
0%
b) acetal
0%
c) ethyl acetate
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d) acetal
Explanation
Answer : (d)
Q.27
The reduction of benzoyl chloride with H2/Pd - BaSO4 produces
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a) Benzoyl cyanide
0%
b) Benzoic acid
0%
c) Benzyl alcohol
0%
d) Benzaldehyde
Explanation
C6H5COCl + H2 → C6H5CHO + HCl Answer : (d)
Q.28
ion Q26) Compound X in follwoing reaction is ....
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a) CH3COOH
0%
b) BrCH2-COOH
0%
c) (CH3CO)2O
0%
d) CHO - COOH
Explanation
Given reaction is Perkin reaction, hence X must be acetic anhydride, since sodium acetate is used as catalyst Answer : (c)
Q.29
Acetaldehyde is used
0%
a) in the preparation of hypnotic drug
0%
b) in the preparation of dyes
0%
c) in the preparation of chloral
0%
d) all are correct
Explanation
Answer : (d)
Q.30
Aldol condensation will not be obsrved in
0%
a) Ethanal
0%
b) Hexanal
0%
c) Phenyl acetaldehyde
0%
d) Chloral
Explanation
Chloral (CC3CHO) does not have any αhydrogen atom and hence does not undergo aldol condensation Answer : (d)
0 h : 0 m : 1 s
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