MCQs on Aldehydes & Ketones

MCQs on Aldehydes & Ketones ........ Unit # 

1.         Aldehydes and ketones are commonly referred to as:
            (a)        Ethers                                                  (b)        Carbonyl compounds
            (c)        Phenols                                                (d)       Saturated H.C.

2.         Which one is the structural formula of carbonyl group?
                          O                                                                    O
                          ||                                                                    ||
            (a)        –C–OH                                               (b)        –C–X

                          O                                                                    O
                          ||                                                                     ||
            (c)        –O–                                                     (d)       –C–O–R

3.         Which one is not the general formula of aldehydes?
            (a)        CnH2n+1……CHO                               (b)        CnH2n+2CO
            (c)        CnH2nO                                               (d)       CnH2nO2

4.         In aldehydes, one of the two available valencies of the carbonyl group is always attached to:
            (a)        Carbon atom                                       (b)        Hydrogen atom
            (c)        Nitrogen atom                                     (d)       None of the above

5.         The type formula of aldehyde is:
            (a)        R2CO                                                  (b)        R2CO2
            (c)        RHCO                                                 (d)       RHCO2

6.         The formula of butyr aldehyde is:
            (a)        C4H8O                                                 (b)        C3H8CO
            (c)        CH3–CH2–CH2–CHO                            (d)       C3H7–CHO
           
7.         Formalin is an aqueous solution of:
            (a)        Formic acid                                         (b)        Formaldehyde
            (c)        Acetaldehyde                                      (d)       Acetic acid

8.         On evaporating aqueous formaldehyde (formalin) solution, a crystalline solid known as hydrated para-formaldehyde is formed having formula:
            (a)        (CH2O)n.H2O                                      (b)        (HCHO)n.H2O
            (c)        (CHO)n.H2O                                       (d)       Both (a) and (b)

9.         Oxidation of aldehydic group by acidified K2Cr2O7 gives:
            (a)        Ketone                                               (b)        Ester
            (c)        Carboxylic acid                                   (d)       Alcohol

10.       Aldehydes on reduction (hydrogenation) give:
            (a)        Ketone                                               (b)        Primary alcohol
            (c)        Carboxylic acid                                   (d)       Ester

11.       The formula of hydroxalamine is:
            (a)        NH2OH                                               (b)        H2N–NH–C6N5
            (c)        (CH2)6N4 (Hexamethylene tetramine)     (d)       All of the above

12.       The formula of phenyl hydrazine is:
            (a)        H2NOH                                               (b)        H2N–NH–C6H5
            (c)        (CH2)6N4                                            (d)       None of the above

13.       Fehling’s solution is an aqueous solution containing:
            (a)        CuSO4                                                (b)        Tartaric acid (Sod.Pot.tartarate)
            (c)        NaOH                                                 (d)       All of the above

14.       It is an alkaline solution of tartarate complex of Cu (II):
            (a)        Tollen’s reagent                                   (b)        Rochelle salt
            (c)        Fehling’s solution                                (d)       Nesseler’s reagent

15.       Which of the following tests is used for detection of aldehydic group in organic compound?
            (a)        Fehling’s test                                       (b)        Tollen’s test
            (c)        Baeyer’s test                                       (d)       Both (a) and (b)

16.       The formula of Fehling’s solution is conveniently represented as:
            (a)        Cu(OH)2                                              (b)        CuSO4
            (c)        NaOH                                                 (d)       [Ag(NH3)2OH]

17.       Fehling’s solution behaves as:
            (a)        Reducing agent                                   (b)        Oxidizing agent
            (c)        Both (a) and (b)                                  (d)       Neither (a) and (b)

18.       Aldehydes are oxidized to carboxylic acid by oxidizing agent like Fehling solution while the cupric ions (Cu2+) of Cu(OH)2 (Fehling solution) are reduced to:
            (a)        Copric oxide                                       (b)        Cuprous sulphide
            (c)        Cupric chloride                                   (d)       Cuprous oxide (Cu2O)

19.       Aqueous ammonical silver nitrate solution is called:
            (a)        Benedict’s reagent                              (b)        Nesseler’s reagent
            (c)        Tollen’s reagent                                   (d)       Fehling’s solution

20.       Tollen’s reagent is an ammonia-silver complex formulated as:
            (a)        Cu(OH)2                                              (b)        Cu2O
            (c)        [Ag(NH3)2]OH                                    (d)       H2NOH

21.       Tollen’s reagent is readily reduced by aldehydes to metallic silver while aldehydes itself oxidizes to carboxylic acid.  This reaction is known as:
            (a)        Tollen’s test                                         (b)        Silver mirror test
            (c)        Fehling’s test                                       (d)       Both (a) and (b)

22.       A compound containing aldehydic group and alcoholic group is known as:
            (a)        Glycol                                                 (b)        Ketol
            (c)        Glycerol                                              (d)       Aldol

23.       A compound containing ketonic group and alcoholic group is known as:
            (a)        Glycol                                                 (b)        Ketol
            (c)        Glycerol                                              (d)       Aldol

24.       It is a reaction in which two molecules of the same or different carbonyl compounds             (aldehydes/ketones) having a-hydrogen undergo self-addition and condense together to form aldol (b-hydroxy aldehydes) or ketol (b-hydroxy ketones) in slightly alkaline medium
            (a)        Cannizaro’s reaction                           (b)        Haloform reaction
            (c)        Aldol (or ketol) condensation             (d)       Williamson’s Synthesis

25.       Aldol condensation cannot occur between:
            (a)        Two identical or different aldehydes (b)        Two identical or different ketones
            (c)        An aldehyde and a ketone                  (d)       An aldehyde and an ester

26.       Which of the following carbonyl compounds undergo aldol condensation?
            (a)        Ethanal                                              (b)        Formaldehyde
            (c)        Benzaldehyde                                     (d)       Both (a) and (b)

27.       Which of the following carbonyl compounds undergo aldol condensation which has?
            (a)        b-hydrogen                                         (b)        a-hydrogen
            (c)        Active hydrogen                                 (d)       Acidic hydrogen

28.       Cannizaro’s reaction is given by those aldehydes which do not have:
            (a)        b-hydrogen                                         (b)        a-hydrogen
            (c)        Active hydrogen                                 (d)       Acidic hydrogen

29.       Which of the following will not undergo Cannizaro’s reaction?
            (a)        Formaldehyde                                     (b)        Benzaldehyde
            (c)        Acetaldehyde                                      (d)       Both (a) and (b)

30.     Aldehydes having no a-hydrogen, when treated with conc. solution of an alkali, undergo self-oxidation-reduction reaction in which one molecule of aldehyde is reduced to alcohol while the other molecule is oxidised to carboxylic acid (which form salt with alkali).  This reaction is called:
            (a)        Disproportionation reaction                (b)        Cannizaro’s reaction
            (c)        Both (a) and (b)                                 (d)       Neither (a) and (b)

31.       Cannizaro’s reaction is an example of:
            (a)        Disproportionation reaction                (b)        self oxidation reduction
            (c)        Both (a) and (b)                                 (d)       Neither (a) and (b)

32.       The formula of haloform (Trihalo methane) is:
            (a)        CH2X2                                                 (b)        CHX3
            (c)        CH3X                                                  (d)       CX4

33.       CHI3 is the formula of:
            (a)        Chloroform                                         (b)        Carbon tetraiodide
            (c)        Iodoform                                             (d)       Bromoform

34.       Haloform or trihalomethane reaction is given by those aldehydes or ketones which contains:
            (a)        Vinyl group                                         (b)        Alkyl group
            (c)        Phenyl group                                       (d)       Acetyl group (–COCH3)

35.       Which of the following carbonyl compounds undergo haloform reaction?
            (a)        Acetone (CH3–CO–CH3)                   (b)        3-pentanone (C2H5–CO–C2H5)
            (c)        Formaldehyde (H–CHO)                    (d)       Ethanal (CH3–CO–H)

36.       Ethanal does not undergo Haloform reaction although it possesses acetyl group.  Which of the following statements is correct regarding this discrepancy?
            (a)        It does not possess acetyl group         (b)        It has a-hydrogen
            (c)        It does not has a-hydrogen                (d)       It exists in hydrated form, CH3.CHO.(H2O)n in                                                                                aqueous solution

37.       Formaldehyde reacts with ammonia to give a white solid, hexamethylene tetramine (methanamine) which have formula _______?
            (a)        (CH2)6N4                                             (b)        (CH2)3N3(NO2)3
            (c)        NH2OH
38.       Hexamethylene tetramine (methanamine) is used in medicine as:
            (a)        Fungicide                                            (b)        Viricide
            (c)        Diuretic                                               (d)       Urinary antiseptic

39.       The medical name of hexamethylene tetramine is:
            (a)        Urotropine                                           (b)        Atropine
            (c)        Atenolol                                              (d)       Cyclonite

40.       Hexamethylene tetramine (methanamine) gives a powerful explosive on nitration which is called:
            (a)        Urotropine                                           (b)        Methyl dopa
            (c)        Diuretic                                               (d)       Cyclonite

41.       In presence of dilute base, formaldehyde reacts with phenol to produce a mixture of:
            (a)        Methylol phenols                                (b)        Bakelite
            (c)        Cyclonite                                             (d)       Polythene

42.       Which of the following scientists prepared the first synthetic plastic Bakelite in 1909?
            (a)        Boyle                                                   (b)        Backeland
            (c)        Backsmith                                           (d)       Dalton


43.       Leo Backeland prepared _______, by the polymerization of methylol phenols under heat and             pressure:
            (a)        Benzene                                              (b)        Cyclonite
            (c)        Urotropine                                           (d)       Bakelite

44.       Which of the following reactions give acetones?
            (a)        By oxidation of sec. propyl alcohol    (b)        By dehydrogenation of 2-propanol
            (c)        By dry distillation of calcium acetate (d)       By hydrolysis of propyne
            (e)        All of the above

45.       Ketones on catalytic or chemical reduction give:
            (a)        Secondary alcohol                               (b)        Primary alcohol
            (c)        Carboxylic acid                                   (d)       Tertiary alcohol

48.       Ketones are oxidized to form carboxylic acid having one carbon atom _____ than parent ketone.
            (a)        Less                                                 (b)        More
            (c)        None of the above                              (d)       Some time less and some time more

46.       Which of the following reactions would yield aldehyde?
            (a)        Oxidation of primary alcohols by acidified K2Cr2O7
            (b)        Dehydrogenation of primary alcohols in presence of Cu-Ni couple
            (c)        Dehydrohalogenation of alkyl halide
            (d)       Both (a) and (b)

47.       Which of the following reactions would give methanal?
            (a)        By oxidation of methanol
            (b)        By dehydrogenation of methyl alcohol
            (c)        By dry distillation of calcium formate (HCOO)2Ca  = HCHO + CaCO3
            (d)       All of the above





























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