Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

 Multiple Choice QuestionsMultiple Choice Questions

21.

Phenol and benzoic acid may be distinguished by :

  • NaHCO3

  • NaOH

  • Na

  • PCl5


A.

NaHCO3

Phenol and benzoic acid can be distinguished by NaHCO3 .Being stronger acid , only benzoic acid reacts with it .


22.

Most acidic is :


D.

Phenol is acidic in nature and the acidic nature of phenol is increased by the presence of - I (electron attracting) groups at o - and / or p - position of the - OH group .However benzoic acid is more acidic than nitro - phenol .


23.

Lucas reagent reacts fastest with :

  • butanol - 1

  • butanol - 2

  • 2 - methyl - propanol - 2

  • 2 - methyl - propanol - 1


C.

2 - methyl - propanol - 2

Lucas reagent (ZnCl2/HCl) reacts fastest with 3° alcohols such as 2 - methyl propanol - 2 [(CH3)3-C-OH] .


24.

PCl X alc. KOH Y conc. H2SO4 Z

Here Z is :

  • CH3-CH2-CH2-OH

  • (CH3)2-C-OH

  • CH3-CH(OH)-CH3

  • none of above


C.

CH3-CH(OH)-CH3

CH3-CH(OH)-CH3 PCl5 CH3-CH(Cl)CH3 alc. KOH CH3-CH=CH2 H2O / conc. H2SO4 Z


25.

The major organic product in the reaction,

CH3 -O- CH(CH3)2 + HI → Product is:

  • CH3OH + (CH3)2 + CHI

  • ICH2OCH(CH3)2

  • CH3O CI(CH3)2

  • CH3O CI(CH3)2


D.

CH3O CI(CH3)2

CH subscript 3 minus straight O minus CH left parenthesis CH subscript 3 right parenthesis subscript 2 space plus space HI space rightwards arrow with 373 space straight K on top space straight H subscript 3 Cl space plus space left parenthesis CH subscript 3 right parenthesis CHOH
In the case of unsymmetrical ether, the alkyl halide is always formed from a smaller alkyl group. This happens so because I- ion being larger in size approaches smaller alkyl group to avoid steric hindrance.
554 Views

26.

In Williamson's synthesis, ethoxyethane is prepared by :

  • passing ethanol over heated alumina

  • heating sodium ethoxide with ethyl bromide

  • treating ethyl alcohol with excess of H2SO4 at 430-440 K

  • heating ethanol with dry Ag2O


B.

heating sodium ethoxide with ethyl bromide

In Williamson's synthesis, ethoxyethane is prepared by heating sodium ethoxide with ethyl bromide. It can be represented by the following equation:

CH3CH2ONaSodium ethoxide + C2H5BrBromoethane Williamson's synthesis CH3CH2OCH2CH3Ethoxyethane + NaBr


27.

Compound reacting with alkaline KMnO4 :

  • (CH3)3-C-OH

  • (CH3)2-CH-OH

  • (CH3)3-C-CH2OH

  • none of the above


B.

(CH3)2-CH-OH

Only 1° alochol and 2° alcohol react with alkaline KMnO4 .

(CH3)2-CH-OHAlcohol KMnO4 CH3-CO||-CH3Ketone [O] CH3COOHAcid


28.

Phenol reacts with chloroform in presence of

  • H2SO4

  • KOH

  • NaNO2/ HCl

  • G.R.


B.

KOH

Phenol reacts with chloroform in presence of potassium hydroxide to form salicylaldehyde.


29.

Phenol on reaction with Br2 gives :

  • O - Bromo phenol

  • p - Bromo phenol

  • 2 , 4 , 6 tribromo phenol

  • 1 , 3 , 5 tribromo benzene


C.

2 , 4 , 6 tribromo phenol

Phenol reacts with Br2 as follows ;

 + Br2 


30.

Assertion : t-Butyl methyl ether is not prepared by the reaction of t-butyl bromide with sodium methoxide.

Reason : Sodium methoxide is a strong nucleophile.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


B.

If both assertion and reason are true but reason is not the correct explanation of assertion.

In Williamson's synthesis, if a tertiary alkyl halide is used, an alkene is the only reaction product and no ether is formed.

(CH3)3CBr + NaOCH3 → (CH3)2C=CH2 + NaBr

It is because alkoxides are not only nucleophiles but also strong bases as well. They react with alkyl halides leading to elimination reaction.