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
Nice questions for practice
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