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12th Standard Chemistry English Medium Carbonyl Compounds and carboxylic acids Reduced Syllabus Important Questions With Answer Key 2021

12th Standard

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 100

    Multiple Choice Questions

    15 x 1 = 15
  1. Predict the product Z in the following series of reactions Ethanoic acid \(\overset { { PCI }_{ 5 } }{ \longrightarrow } X\overset { { C }_{ 6 }{ H }_{ 6 } }{ \underset { Anhydrous \ AlcI }-_{3}{ \longrightarrow } } Y\overset { 1){ CH }_{ 3 }MgBr }{ \underset { II){ H }_{ 3 }{ O }^{ + } }{ \longrightarrow } } Z.\)

    (a)

    (CH3)2 C(OH)C6H5

    (b)

    CH3CH(OH)C6H5

    (c)

    CH3CH(OH)CH2- CH3

    (d)

  2. CH3Br \(\overset { KCN }{ \longrightarrow } (A)\overset { { H }_{ 2 }{ O }^{ + } }{ \longrightarrow } (B)\overset { { PCl }_{ 5 } }{ \longrightarrow } \) (C) product (c) is

    (a)

    acetylchloride

    (b)

    chloro acetic acid

    (c)

    \(\alpha\)- chlorocyano ethanoic acid

    (d)

    none of these

  3. Assertion: p – N, N – dimethyl amino benzaldehyde undergoes benzoin condensation
    Reason: The aldehydic (-CHO) group is meta directing.
    Codes:
    (A) if both assertion and reason are true and reason is the correct explanation of assertion.
    (B) if both assertion and reason are true but reason is not the correct explanation of assertion.
    (C) assertion is true but reason is false
    (D) both assertion and reason are false

    (a)

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

    (b)

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

    (c)

    assertion is true but reason is false

    (d)

    both assertion and reason are false

  4. Which one of the following reaction is an example of disproporationation reaction

    (a)

    Aldol condensation

    (b)

    cannizaro reaction

    (c)

    Benzoin condensation

    (d)

    none of these

  5. In which of the following reactions new carbon – carbon bond is not formed?

    (a)

    Aldol condensation

    (b)

    Friedel craft reaction

    (c)

    Kolbe’s reaction

    (d)

    Wolf kishner reduction

  6. An alkene “A” on reaction with O3 and Zn - H2O gives propanone and ethanol in equimolar ratio. Addition of HCl to alkene “A” gives “B” as the major product. The structure of product “B” is

    (a)

    \(Cl-{ CH }_{ 2 }-CH_{ 2 }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { CH_{ 3 } }{ | } }{ CH } } \)

    (b)

    \({ H }_{ 3 }C-{ CH }_{ 2 }-\overset { \overset { CH_{ 2 }Cl }{ | } }{ CH } -{ CH }_{ 3 }\)

    (c)

    \(\\ { H }_{ 3 }C-{ CH }_{ 2 }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { CL{ } }{ | } }{ C } } -{ CH }_{ 3 }\)

    (d)

    \({ H }_{ 3 }C-{ CH }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { Cl }{ | } }{ C } } \)

  7. Give the common and IUPAC name of the compound HO-CH2-\(\underset { \overset { | }{ OH } }{ CH } \)-CHO

    (a)

    glyceraldehyde, hydroxy prop anal

    (b)

    glyceraldehyde, 2, 3 - dihydroxy prop anal

    (c)

    crotonaldehyde, hydroxy propanal

    (d)

    crotonaldehyde, 2, 3 - dihydroxy propanal

  8. Cannizaro reaction is not given by

    (a)

    (b)

    (c)

    CH3CHO

    (d)

    HCHO

  9. Which among the carbonyl compounds cannot be prepared by Rosenmund reduction?

    (a)

    Ketones

    (b)

    Formaldehyde

    (c)

    Acetaldehyde

    (d)

    Both (a) and (b)

  10. Schiff's reagent gives pink colour with

    (a)

    acetone

    (b)

    acetaldehyde

    (c)

    ethyl alcohol

    (d)

    methyl acetate

  11. Tincture benzoin is obtained from

    (a)

    benzoyl chloride

    (b)

    benzoin

    (c)

    benzyl alcohol

    (d)

    benzoic acid

  12. The formation of cyanohydrin from a ketone is an example of

    (a)

    electrophilic addition

    (b)

    nucleophilic addition

    (c)

    nucleophilic substitution

    (d)

    electrophilic substitution

  13. Which compound on strong oxidation gives propionic acid?

    (a)

    \({ CH }_{ 3 }-\underset { \overset { | }{ OH } }{ CH } -{ CH }_{ 3 }\)

    (b)

    \({ CH }_{ 3 }-CO-{ CH }_{ 3 }\)

    (c)

    \({ CH }_{ 3 }-\overset { \underset { | }{ { CH }_{ 3 } } }{ \underset { \overset { | }{ { CH }_{ 3 } } }{ C } } -OH\)

    (d)

    \({ CH }_{ 3 }-{ CH }_{ 2 }{ CH }_{ 2 }OH\)

  14. It is a powerful acetylating agent for compounds containing -OH group and - NH group.

    (a)

    CH3CONH2

    (b)

    CH3COOH

    (c)

    CH3COCl

    (d)

    CH3COOCH3

  15. Partial reduction of acetic acid in the presence of LiAl H4 results in the formation of ________.

    (a)

    ethane

    (b)

    ethanol

    (c)

    ethene

    (d)

    ethyne

  16. 2 Marks

    10 x 2 = 20
  17. How is propanoic acid is prepared starting from
    (a) an alcohol
    (b) an alkylhalide
    (c) an alkene

  18. A hydrocarbon A (molecular formula C8H10)on ozonolysis gives B (C4H6O2) only. Compound C (C3H5Br) on treatment with magnesium in dry ether gives (D) which on treatment with CO2 followed by acidification gives(C). Identify A) Band C.

  19. Give the characteristics of image formed by a plane mirror.

  20. What are the Cartesian sign conventions for a spherical mirror?

  21. Name one reagent used to distinguish acetaldehyde and acetone.

  22. Does formaldehyde undergo aldol condensation? Justify your answer

  23. What is formalin? Write its use.

  24. Arrange the following in increasing order of reactivity towards nucleophilic addition HCHO) CH3CHO and CH3COCH3

  25. What is DIBAL -H? What is it used for?

  26. What are carboxylic acids?

  27. 3 Marks

    10 x 3 = 30
  28. An alkene (A) on ozonolysis gives propanone and aldehyde (B). When (B) is oxidised (C) is obtained. (C) is treated with Br2/P gives (D) which on hydrolysis gives (E). When propanone is treated with HCN followed by hydrolysis gives (E). Identify A, B, C, D and E.

  29. How is acetaldehyde prepared by the ozonolysis of CH3CH=CHCH3?

  30. Formaldehyde and benzaldehyde give Cannizaro reaction but acetaldehyde does not - account for this.

  31. Explain the isomerism exhibited by carboxylic acids.

  32. What happens when the following compounds are treated with dilute NaOH solution in cold?
    (i) propanal
    (ii) (CH3)3C-CHO

  33. How will you convert benzaldehyde to
    (I) C6H5COOH
    (ii) C6HsCH2OH
    (iii) C6HSCH3

  34. Organic compound with molecular formula C3H6O has two isomers (A) and (B). (A) on heating with NaOH in I2 forms a yellow precipitate while (B) does not. Identify the isomers A and B and explain the reactions.

  35. Formic acid reduces Tollen's reagent but acetic acid does not - Give reasons.

  36. Complete the following reactions
    (i) CH3COCI+NH2
    (ii) CH3COCI + C2H5OH⟶

  37. Give the IUPAC names for the following:
    (i) Crotonaldehyde
    (ii) Methyl n-propyl ketone
    (iii) Phenyl acetaldehyde.

  38. 5 Marks

    7 x 5 = 35
  39. How are the following conversions effected
    (a) propanal into butanone
    (b) Hex-3-yne into hexan-3-one.
    (c) phenylmethanal into benzoic acid
    (d) phenylmethanal into benzoin

  40. Complete the following reaction
    \({ CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 2 }-\underset { \overset { || }{ O } }{ C } -{ CH }_{ 3 }\overset { HO-{ CH }_{ 2 }-{ CH }_{ 2 }-OH }{ \underset { { dry }{ HCl} }{ \longrightarrow } } ?\)

  41. Illustrate the reducing property of acetaldehyde with examples

  42. Explain why carboxylic acids behave as acids. Discuss briefly the effects of electron withdrawing and donating substituents on acid strength of carboxylic acids.

  43. An organic compound A (C2H3N) on reduction with SnCI2/HCI gives B (C2H4O) which reduces Tollen's reagent. Compound B on reduction with N2H/C2HsONa gives C (C2H6). Identify the compounds A, B and C. Explain the reactions involved.

  44. An organic compound (A) of molecular formula C7Hon oxidation with air and in presence of V2O5 to form (B) of molecular formula C7H6O. (B) on reduction with lithium aluminium hydride to form (C) of . molecular formula C7H5O. Identify (A)(B) and (C) and explain th.e reactions.

  45. Compound (A) with Molecular formula C7H6O does not reduce Fehling's solution. Compound (A) reacts with acetone in the presence of NaOH to give a compound (B) which is an α, β-unsa,turated compound. Further (A) reacts with dimethyl aniline in the presence of cone, H2SO4 to give compound (C) which is a dye. Identify (A) (B) and (C). Explain the reactions.

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