jee main previous year papers questions with solutions chemistry alcoholsetherscarobonyls and carboxylic acids

JEE Main Previous Year Papers Questions With Solutions Chemistry  Alcohols,Ethers,Carobonyls and Carboxylic Acids

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Ans.(2) Aldehydic group gets oxidised to carboxylic group. Doyble bond breaks and carbon gets oxidised to carboxylic group.

3.An ether is more volatile than an alcohol having the same molecular formula. This is due to               (2003)
1)alcohols having resonance structures
2)inter-molecular hydrogen bonding in ethers
3)inter-molecular hydrogen bonding in alcohols
4) dipolar character of ethers
Ans.(3) Alcohols are associate liquids.

4.When CH₂ = CH – COOH is reduced with  LiAlH₄, the compound obtained will be (2003)
1)CH₂ = CH-CH₂OH ‘
2)CH₃ – CH₂ – CHjOH
3)CH₃ – CHj – CHO
4)CH₃ – CH₂ – COOH
Ans.(1) LiA/H₄ can reduce COOH group and not the double bond.
CH₂ = CH – COOH is reduced to give CH₂ = CH – CH2OH

5.During dehydration of alcohols to alkenes by heating with cone. H₂S0₄ the initiation step is  (2003)
1)formation of carbocation
2)elimination of water
3)formation of an ester
4)protonation of alcohol molecule
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6.Consider the apidity of the carboxylic acids: Most acidic is       (2004)
1)PhCOOH
2)o – N0₂C₆H₄C00H
3)p – N0₂C₆H₄C00H
4)m – N0₂C₆H₄C00H
Ans.(2) Orthonitrobenzoic acid.

7.On mixing ethyl acetate with aqueous sodium chloride, the composition of the resultant solution is     (2004)
1)CH₃COOC₂H₅ + NaCl
2)CH₃C1 + C₂H₅COONa
3)CH3COCl + C₂H₅OH + NaOH
4)CH₃COONa + C₂H₅OH
Ans.(1) No chemical reaction occurs.

8.Acetyl bromide reacts with excess of CH₃MgI  followed by treatment with a saturated solution of NH₄C1 given                       (2004)
1)acetone                 2)     acetyl iodide
3)2-methyl-2-propanol      4)acetamide
Ans.(3) Gives tertiary alcohol.

9.Which of the following undergoes reaction  with 50% sodium hydroxide solution to give the corresponding alcohol and acid ? (2004)
1)Phenol                              2)     Benzoic acid
3) Butanal                          4) Benzaldehyde
Ans.(4)Benzaldehyde does not contain a-hydrogen. Hence goes for cannizarro’s reaction forming alcohol and acid.

10.Among the following compound which can be  dehydrated very easily is                 (2004)

Ans.(3) Tertiory alcohols will undergo more easily  dehydration than secondary and primary.

11.The best reagent to convert pent-3- en-2-ol  into pent-3-en-2-one is    (2005)
1) Acidic permanganate
2)Acidic dichromate
3)Chromic anhydride in glacial acetic acid
4)Pyridinium chloro – chromate
Ans.(3) Conversion of 2 ° alcohol to ketone with mild oxidant.

12.Among the following acids which has the  lowest pK_a value?
1)CH₃COOH                     2) HCOOH
3) (CH₃)₂COOH              4) CH₃CH₂COOH
Ans.(2) Most  acidic  is formic  acid.

13.Reaction of cyclohexanone with dimethyl-  amine in the presence of catalytic amount of
an acid forms a compound if water during the  reaction is continuously removed. The  compound formed is generally known as  (2005)
1) a Schiff’s base         2) an enamine
3) an imine                                       4) an amine
Ans.

14.p-cresol reacts with chloroform in alkalin  medium to give the compound A which adds
hydrogen cyanide to form, the compound B.  The latter on acidic hydrolysis gives chiral  carboxylic acid. The structure of the  carboxylic acid is   (2005)

Ans.

15.The increasing order of the rate of HCN  addition to compounds A – D is                     (2006)
(A) HCHO                                       (B) CH3COCH3
(C) PhCOCHj                             (D) PhCOPh
1)A<B<C<D           2)D<B<C<A
3)D<C<B<A       4)C<D<B<A
Ans.(3) Least  reactive is  PH-CO-PH.

16. Phenyl magnesium bromide reacts with  methanol to give(2006)
1)a mixture of anisole and Mg(OH)Br
2)a mixture of benzene and Mg(OMe)Br
3)a mixture of toluene and Mg(OH)Br
4)a mixture of phenol and  Mg(Me)Br
Ans.(2) Benzene is formed.

Ans.(4) Iodoform is given by methyl ketone.

18.The correct order of increasing acid strength  of the compounds is
a)CH₃C0₂H    b) Me0CH₂C0₂H
c) CF₃Co₂H        d) (Me)₂ C0₂H
Ans.(3) CFjCOOH is most acidic.

19.The structure of the compound that gives a  tribromo derivative on treatment with  bromine water is  (2006)

Ans.(1) ortho and para positions of bromiantion, to -OH group.

Ans.(2) Dichlorocarbene is electrophile in Reimer- Tiemann reaction.

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Ans.(3) Any aliphatic carbon with hydrogen attached to it, in combination with benzene ring, will be oxidized to benzoic acid by KMn0₄ / H⁺.

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24.A liquid was mixed with ethanol and a drop of concentrated H.SO. was added. A  compound with a fruity smell was formed. The liquid was               (2009)
1) CH₃OH                                         2) HCHO
3) CH₃COCH₃                               4) CH₃COOH
Ans.

25.The major product obtained on interaction of  phenol with sodium hydroxide and carbon dioxide is       (2009)
1) benzoic acid                   2) salicylaldehyde
3) salicylic acid                  4)phthalic acid
Ans.

26.Which of the following on heating with aqueous KOH, produces acetaldehyde ?  (2009)
1) CH₃ COCl                 2) CH₃CH₂Cl
3) CH₂Cl CH₂Cl           4) CH₃CHCl₂
Ans.

Ans.(2) Hydride transfer is the slowest step.

28.From Amongst the following alcohols the one  that would react fastest with conc.HCl and anhydrous ZnCl₂, is (2010)
1)2- Butanol
2)2- Methylpropan-2-ol
3)2-Methylpropanaol
4) 1-Butanol
Ans.(2) 3 ° alcohols react fastest with ZnCl₂/conc. HC1 due to formation of 3 ° carbocation. 2-Methylpropan-2-ol is the only 3 ° alcohol

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30.Silver Mirror test is given by which one of  the following compounds ?                                 (2011)
1) Formaldehyde                   2) Benzophenone
3) Acetaldehyde                     4) Acetone
Ans.

31. Trichloroacetaldehyde was subjected to  Cannizzaro’s reaction by using NaOH. The mixture of the products contains sodium trichloroacetate and another compound. The other compound is         (2011)
1)2,2,2-Trichloropropanol
2)Chloroform
3)2,2,2-TrichIoroethanol
4)Trichloromethanol
Ans.

32.The strongest acid amongest the following  compounds is    (2011)
1)CH₃CH₂CH(CZ)C0₂H
2)ClCH₂CH₂CH₂  COOH
3)CH3COOH
4) HCOOH
Ans.

33.Sodium ethoxide has reacted with ethanoyl  chloride. The compound that is produced in the above reaction is                 (2011)
1) Ethyl chloride                       2) Ethyl ethanoate
3) Diethyl ether                           4) 2 – Butanone
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34.Which of the following reagents may be used  to distinguish between phenol and benzoic acid?                     (2011)
1) Molisch reagent                 2) Neutral FeCl₃
3) Aqueous NaOH                 4) Tollen’s reagent
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35. Iodofrom can be prepared from all except  (2012)
1) Ethyl methyl ketone 2) Isopropy alcohol
3)3-Methyl-2-butanone
4)Isobuty alcohol
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36.In the given transformation, which of the following  is the most appropriate reagent ?                   (2012)

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37.Arrange the following compounds in order of  decreasing acidity  (2013)

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38.Compound(A), C₈H₉Br, gives white precipate when warmed with alcoholic AgN0₃. Oxidation of (A) gives an acid (B), C₈H₆0₄. (B) easily forms anhydride on heating. Identify the compound (A).           (2013)

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39.An organic compound A upon reaction NH₃ gives B. On heatinmg B gives C. C in presence of KOH reacts with Br₂ to give CH₃CH₂NH₂  A is     (2013)

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40.An unknown alcohol is treated with the “Lucas reagent”to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism (2013)
1)secondary alcohol by S_N1
2)tertiary alcohol by S_N1
3)secondary alcohol by S_N2
4)tertiary alcohol by S_N2
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41.Sodium phenoxide when heated with C0₂ under pressure at 125 °C yields a product which on a acetylation produces C.

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42.The most suitable reagent for the conversion of R – CH₂ – OH -> R – CHO is (2014)
1)PCC (Pyridinium Chlorochromate)
2)KMn0₄
3)K₂Cr₂0₇
4) Cr0₃
Ans.(1) Most suitable reagent for the conversion of 1 ° alcohol to aldehyde is “PCC”.

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