Organic Chemistry Flashcards
1
Q
- Which of the following statements about carbon is NOT correct?
A. Carbon forms strong covalent bonds to itself, allowing chains and rings to be made.
B. Carbon expands its valence shell to accommodate more than eight electrons and thus forms double and triple bonds.
C. Carbon and hydrogen have similar electronegativity and form strong bonds to each other, thus avoiding the high reactivity shown by metal hydrides.
D. Carbon forms strong covalent bonds to elements like nitrogen and oxygen because it does not have lone pairs of valence electrons to destabilize the bonds.
A
B. Carbon expands its valence shell to accommodate more than eight electrons and thus forms double and triple bonds.
2
Q
Which statement about bonding is TRUE?
A. A π bond is as twice as strong as a σ bond
B. A double bond consists of two π bonds
C. A σ bond has cylindrical symmetry about the bonding axis.
D. A π bond results from the sideways overlap of hybridized orbitals.
A
C. A σ bond has cylindrical symmetry about the bonding axis.
3
Q
How many σ and π bonds are in acetylene?
A. 2σ, 2π
B. 3σ , 2π
C. 2σ, 3π
D. 3σ, 3π
A
B. 3σ , 2π
4
Q
What is the bond angle and molecular geometry around C in CH2=CH2?
A. 120°, tetrahedral
B. 109.5°, tetrahedral
C. 120°, planar
D. 109.5°, planar
A
C. 120°, planar
5
Q
What is the hybridization of O in CH3OH?
A. sp3
B. sp2
C. sp
D. sp3d
A
A. sp3
Oxygen in methanol has two lone pairs and forms two sigma bonds (one with hydrogen and one with carbon), making it have a tetrahedral electron geometry, which corresponds to sp³ hybridization.
6
Q
Which of the following orbitals provide the most efficient overlap?
A. s-s
B. sp3 - sp3
C. sp-sp
D. p-p
A
C. sp-sp
7
Q
How many constitutional isomers are possible for the molecular formula C5H12?
A. 1
B. 2
C. 3
D. 4
A
C. 3
8
Q
How many distinct branched alkanes are there with the formula C6H14?
A. 1
B. 2
C. 3
D. 4
A
D. 4
9
Q
Which of the following is TRUE for an optically active compound?
A. The molecular configuration is chiral.
B. The molecular configuration is achiral.
C. The compound is a racemic mixture of enantiomers.
D. The molecular configuration must have two or more stereogenic centers.
A
A. The molecular configuration is chiral.
10
Q
Compounds which have different arrangements of atoms in space while having the same atoms bonded to each other are
A. constitutional isomers
B. functional group isomers
C. coordination isomers
D. Stereoisomers
A
D. Stereoisomers
11
Q
Which of the following statements describes enantiomers?
A. They are achiral stereoisomers.
B. They are stereoisomers having a mirror plane of symmetry.
C. They are stereoisomers having non-identical mirror image configurations.
D. They are stereoisomers that do not have non-identical mirror image configurations.
A
C. They are stereoisomers having non-identical mirror image configurations.
12
Q
Which substance can exist in enantiomeric forms?
A. 3-methylpentane
B. 2-methylpentane
C. 3-methyl-1-butanol
D. 2-methyl-1-butanol
A
D. 2-methyl-1-butanol
13
Q
A racemic mixture consists of equal quantities of
A. cis-trans isomers
B. diastereomers
C. enantiomers
D. structural isomers
A
C. enantiomers
14
Q
Which of the following is NOT an addition reaction?
A. Hydration
B. Dehydration
C. Halogenation
D. Hydrohalogenation
A
B. Dehydration
15
Q
In this type of reaction, one sigma bond breaks and another forms at the same carbon atom.
A. Addition
B. Elimination
C. Substitution
D. Rearrangement
A
C. Substitution
In a substitution reaction, one sigma bond breaks and another sigma bond forms at the same carbon atom. This involves replacing one atom or group in the molecule with another, typically resulting in the same carbon atom being bonded to different groups.
16
Q
During symmetrical bond breaking, ____ are formed.
A. Radicals
B. Electrophiles
C. Nucleophiles
D. None of the above
A
A. Radicals
17
Q
All of the following are electrophiles EXCEPT
A. Br
B. BF3
C. AICI3
D. NH3
A
D. NH3
Br (Bromine): This can act as an electrophile, especially in reactions where it forms a positive ion (Br⁺).
BF₃ (Boron trifluoride): This is a strong electrophile due to the electron deficiency of boron, which has only six electrons in its valence shell.
AlCl₃ (Aluminum chloride): This is also a strong electrophile, particularly in Lewis acid-base reactions, as it can accept electron pairs.
NH₃ (Ammonia): Ammonia is a nucleophile because it has a lone pair of electrons on the nitrogen atom, allowing it to donate electrons rather than accept them.
18
Q
Which of the following statements is FALSE?
A. It is not necessary for a nucleophile to have an unshared electron pair.
B. A species can react as an electrophile if it contains an atom (other than hydrogen) with an incomplete valence octet.
C. A species can react as an electrophile, even if it has one or more unshared electron pairs.
D. Any species bearing a lone pair can normally react as a nucleophile.
A
A. It is not necessary for a nucleophile to have an unshared electron pair.
19
Q
Liquified petroleum gas is mainly composed of
A. Methane and Ethane
B. Ethane and Propane
C. Propane and Butane
D. Butane and Hexane
A
C. Propane and Butane
20
Q
The hydrocarbon having the lowest boiling point is
A. CH4
B. C2H4
C. C4H10
D. C6H6
A
A. CH4
21
Q
Compared to ionic compounds of similar molar mass, hydrocarbons typically have
I. Higher water solubility II. Higher melting points
A. I only
B. II only
C. both I and II
D. neither I nor II
A
D. neither I nor II
22
Q
Which class of compounds consist exclusively of saturated hydrocarbons?
A. Alkenes
B. Aromatics
C. Alkynes
D. Alkanes
A
D. Alkanes
23
Q
Alkanes undergo halogenation via
A. free radical substitution
B. electrophilic substitution
C. electrophilic addition
D. nucleophilic addition
A
A. free radical substitution
24
Q
Alkenes and alkynes, because they contain π bonds, undergo this type of reaction.
A. Electrophilic addition
B. Nucleophilic addition
C. Electrophilic substitution
D. Nucleophilic substitution
A
A. Electrophilic addition
Alkenes and alkynes, due to their π bonds, undergo electrophilic addition reactions. The π electrons in these compounds are electron-rich and can be attacked by electrophiles, leading to the addition of atoms or groups across the double or triple bond. This type of reaction breaks the π bond and forms new σ bonds.
25
Which of the following reactions can reduce an alkene yielding an alkane?
A. Oxidation
B. Bromination
C. Hydrogenation
D. Polymerization
C. Hydrogenation
26
All of the following reactions convert alkenes to alcohols EXCEPT
A. halohydrin formation
B. ozonolysis
C. hydroboration-oxidation
D. oxymercuration-demercuration
B. ozonolysis
27
What is the position of the bromine atom relative to the methyl group in 3-bromotoluene?
A meta
B. para
C. ortho
D. trans
A meta
28
Aromatic compounds undergo substitution reactions instead of addition reactions because
A. the benzene ring is electron rich.
B. the hydrogens of benzene are relatively loosely bound.
C. the benzene ring is sterically crowded hence only substitution can occur.
D. the integrity of the benzene ring and the stable aromatic π system remains intact.
D. the integrity of the benzene ring and the stable aromatic π system remains intact.
Aromatic compounds, like benzene, undergo substitution reactions (such as electrophilic aromatic substitution) because these reactions allow the aromatic stability (the delocalized π system) to remain intact. Addition reactions would disrupt the conjugated π system and break the aromaticity, which is energetically unfavorable. Therefore, substitution reactions are preferred as they maintain the stability of the aromatic ring.
29
Which of the following substituents is NOT an ortho, para directing group in EAS?
A. -CI
B. -OH
C. -NO2
D. -CH3
C. -NO2
30
AlCl3 is a catalyst used in the alkylation and acylation of aromatic compounds. It is a(an)
A. Arrhenius acid
B. Brønsted-Lowry acid
C. Lewis acid
D. Lewis base
C. Lewis acid
AlCl₃ acts as a Lewis acid because it can accept a pair of electrons. In alkylation and acylation reactions (such as the Friedel-Crafts reactions), AlCl₃ accepts an electron pair from the halogen in an alkyl or acyl chloride, facilitating the formation of a carbocation or acylium ion, which then reacts with the aromatic compound.
31
Which of the following is arranged in order of increasing boiling point?
A. 2-methylbutane < n-pentane < butanone < butanol
B. n-pentane <2-methylbutane < butanone < butanol
C. 2-methylbutane < n-pentane < butanol < butanone
D. n-pentane < 2-methylbutane < butanol < butanone
A. 2-methylbutane < n-pentane < butanone < butanol
32
Methanal is used as
A. fuel
B. antiseptic
C. preservative
D. refrigerant
C. preservative
33
The simplest ketone is
A. acetone
B. lactone
C. cyclohexanone
D. ethyl methyl ketone
A. acetone
34
Carbonyl compounds undergo this type of reaction.
A. Electrophilic addition
B. Nucleophilic addition
C. Electrophilic substitution
D. Nucleophilic substitution
B. Nucleophilic addition
Carbonyl compounds, such as aldehydes and ketones, typically undergo nucleophilic addition reactions due to the electrophilic nature of the carbon atom in the carbonyl group (C=O). This makes them susceptible to attack by nucleophiles.
35
Ketones react with reducing agents to form
A. phenols
B. primary alcohols
C. secondary alcohols
D. tertiary alcohols
C. secondary alcohols
Ketones react with reducing agents (like NaBH₄ or LiAlH₄) to form secondary alcohols. The reduction process adds hydrogen to the carbonyl group (C=O) of the ketone, converting it into a hydroxyl group (-OH) attached to a carbon that is connected to two other carbon atoms, forming a secondary alcohol.
36
Which of the following will have the highest boiling point?
A. butane (58 g/mol)
B. propanal (58 g/mol)
C. 1-butanol (60 g/mol)
D. acetic acid (60 g/mol)
D. acetic acid (60 g/mol)
37
Carboxylic acids are more acidic than alcohols because
A. of the increased polarity of the O-H due to the carbonyl group.
B. of the stability of the carboxylate anion formed upon ionization.
C. of the higher K, value.
D. All of the above
D. All of the above
38
Which alkyl halide will most likely react via SN2 mechanism?
A. bromobenzene
B. bromomethane
C. 2-bromo-2-methylpropane
D. 1-bromobutane
B. bromomethane
39
Which chloroalkane undergoes substitution with OH- exclusively by an SN1 mechanism?
A. (CH3)3CCI
B. (CH3)2CHCH2CI
C. CH3CH2CHCICH3
D. CH3CH2CH2CH2CI
A. (CH3)3CCI
40
Among the following group of compounds, which will have the highest boiling point?
A. alkenes
B. alkynes
C. alcohols
D. haloalkanes
C. alcohols
41
An industrial source of alcohol.
A. coal
B. fats
C. sugar
D. ether
C. sugar
42
Which of the following will react faster with HBr?
A. 1-butanol
B. 2-butanol
C. 2-methyl-1-propanol
D. 2-methyl-2-propanol
D. 2-methyl-2-propanol
2-methyl-2-propanol (tert-butanol) will react faster with HBr because it forms a tertiary carbocation upon the loss of its hydroxyl group, which is more stable compared to primary or secondary carbocations. This stability leads to a faster reaction rate in the formation of alkyl halides via an SN1 mechanism. Tertiary alcohols generally react faster than secondary and primary alcohols with HBr.
43
Dehydration of an alcohol yields a(an).
A. alkene
B. alkyne
C. aldehyde
D. ketone
A. alkene
Dehydration of an Alcohol: This process involves the removal of a water molecule (H₂O) from an alcohol, typically under heat and in the presence of an acid catalyst.
The elimination of water results in the formation of a double bond, converting the alcohol into an alkene.
44
Which of the following can react with NaOH?
A phenol
B. ethanol
C. ethylene
D. diethyl ether
A phenol
Phenol can react with NaOH because it is acidic enough to donate a proton (H⁺) to form phenoxide ion (C₆H₅O⁻) and water. Ethanol, ethylene, and diethyl ether are not acidic enough to undergo this reaction with NaOH.
45
A compound having a permanent dipole moment is _____.
A. CO2 B. H2 C. CH4 D. CO
D. CO
CO is a polar molecule due to the difference in electronegativity between carbon and oxygen, leading to a permanent dipole moment. The other options (A. CO2 (linear so ma cancel ra ang each other), B. H2, and C. CH4) are either nonpolar molecules or have symmetrical arrangements that cancel out any dipole moments.
46
Which element can take part in hydrogen bonding?
A. F B. O C. N D. all of them
D. all of them
47
Only dispersion forces are present in _____.
A. HF B. C6H6 C. CO D.C2H5OH
Only dispersion forces are present in B. C6H6 (benzene).
Benzene is a nonpolar molecule, and its interactions are primarily due to dispersion forces (London dispersion forces). The other options—HF (polar), CO (polar), and C2H5OH (ethanol, which has hydrogen bonding)—all exhibit stronger intermolecular forces beyond just dispersion.
48
Polarizability is highest for _____.
A. CH4 B. H2 C. CCl4 D. H2S
C. CCl4
Larger atoms or molecules with more electrons typically have higher polarizability because their outer electrons are further from the nucleus and can be more easily distorted.
49
Which of the following has the lowest boiling point?
A. CH3COCH3 B. CH3OCH3 C. CH3COOH D.CH3CHO
B. CH3OCH3
A. CH3COCH3 (acetone) has a higher boiling point due to its polar nature and the ability to form dipole-dipole interactions.
B. CH3OCH3 (dimethyl ether) is less polar than acetone and does not form hydrogen bonds, resulting in a lower boiling point.
C. CH3COOH (acetic acid) has a relatively high boiling point due to strong hydrogen bonding.
D. CH3CHO (acetaldehyde) is polar and can form dipole-dipole interactions, contributing to a higher boiling point than dimethyl ether.
50
Arrange the following according to increasing boiling point:
W= methyl acetate X= butanal Y= n-butyl alcohol Z = butanoic acid
A. XYZW B. WXYZ C. XWYZ D.WXZY
B. WXYZ
Order of Boiling Points:
Lowest: Methyl acetate (W) and butanal (X) have similar boiling points, but generally, butanal (X) is slightly higher due to its longer carbon chain.
Next: n-Butyl alcohol (Y) has a higher boiling point due to hydrogen bonding.
Highest: Butanoic acid (Z) has the highest boiling point due to strong hydrogen bonding and the ability to form dimers.
51
Which of the following has the lowest boiling point?
A. o-hydroxynitrobenzene
C. p-hydroxynitrobenzene
B. m-hydroxynitrobenzene
D. p-hydroxybenzoyl chloride
A. o-hydroxynitrobenzene
Ortho < Meta < Para in terms of boiling points, with para isomers typically exhibiting the highest boiling points due to reduced steric hindrance and enhanced intermolecular interactions.
Ortho Isomers: These often have the lowest boiling points among the three due to steric strain from substituents being close together. This strain can make the molecule less stable and lead to weaker intermolecular forces.
52
Which of the following statements is correct?
A. The greater the molecular weight, the lower the b.p
B. The greater the molecular attraction, the higher the b.p
C. The greater the molecular attraction, the lower the ∆HV
D. The smaller the molecular weight, the higher the b.p
B. The greater the molecular attraction, the higher the b.p
53
The boiling point of a liquid depends on _____.
A. external pressure C. molecular weight
B. molecular attraction D. all of the above
D. all of the above
54
The vapor pressure of a liquid is _____.
A. Inversely proportional to temperature
B. Directly proportional to temperature
C. Directly proportional to boiling point
D. Directly proportional to melting point
B. Directly proportional to temperature
The vapor pressure of a liquid increases as the temperature increases because more molecules gain enough energy to escape the liquid phase.
55
The vapor pressure of a liquid depends on the _____.
A. amount of liquid C. temperature of the liquid
B. volume of the liquid D. surface area of the liquid
C. temperature of the liquid
56
Which of the following factors will not affect the rate of vaporization of the liquid?
A. temperature B. amount of liquid C. intermolecular forces D. surface area\
B. amount of liquid
57
A liquid having a higher vapor pressure will have _____.
A. higher molecular weight C. higher boiling point
B. lower boiling point D. higher surface area
B. lower boiling point
A higher vapor pressure indicates that the liquid can evaporate more easily at lower temperatures. Consequently, it will reach its boiling point sooner compared to liquids with lower vapor pressures.
58
Which of the following properties indicates very strong intermolecular forces in liquids?
A. very low surface tension C. very low boiling point
B. very low critical temperature D. very low vapor pressure
D. very low vapor pressure
A liquid with strong intermolecular forces will have fewer molecules escaping into the vapor phase, resulting in a lower vapor pressure. This is because the strong forces hold the molecules together more tightly.
59
Which of the following pairs of compounds represents skeletal isomers?
a) 1-butene & 2-butene
b) 2-methylpropene & 1-butene
c) 2-butene & cyclobutene
d) 2-methylpropene & cyclobutene
b) 2-methylpropene & 1-butene
60
Consider the following reaction of cyclohexanol and determine the necessary reagent that would be
appropriate for the given transformation:
cyclohexanol → cyclohexanone
a) Na metal (H2 gas is evolved)
b) H2SO4 , heat (elimination rxn)
c) CH3COOH. H+ (acyl substitution reaction)
d) CrO3, H+ (oxidation rxn)
d) CrO3, H+ (oxidation rxn)
61
Which isomeric pentane has the highest boiling point?
a) n-pentane
b) 2-methylbutane
c) 2,2-dimethylpropane
d) None of these
a) n-pentane
62
Which isomeric pentane gives only one monobromination product?
a) n-pentane
b) 2-methylbutane
c) 2,2-dimethylpropane
d) None of these
c) 2,2-dimethylpropane
63
The following compounds contain carbon but may not be considered organic except ____.
a) ammonium cyanate, NH4CNO
b) carbonic acid, HOCOOH
c) formic acid, HCOOH
d) baking soda, NaHCO3
c) formic acid, HCOOH
64
The reaction H2C=CH2 + H2 ® H3C−CH3 is an example of
a) Substitution
b) Addition
c) Esterification
d) Fermentation
b) Addition
65
Which of the following molecules will not have a dipole moment?
a) CH3Cl
b) CH3OCH3
c) CH2Cl2
d) CCl4
d) CCl4
66
Which of the following compounds has no isomer?
a) CH3CH2CH2Cla
b) CH3CHO
c) CH2=CHCl
d) ClCH2CH2Cl
c) CH2=CHCl
67
Which compound must overcome hydrogen bonds when it boils?
a) Ethyl chloride, CH3CH2Cl
b) Ethylamine, CH3CH2NH2
c) Ethane, C2H6
d) Diethyl ether, C2H5OC2H5
b) Ethylamine, CH3CH2NH2
68
Which force of interaction makes the nonpolar pentane, C5H12 , exist as a liquid?
a) ion–dipole interaction
b) van der Waals forces
c) dispersion forces
d) dipole–dipole attraction
c) dispersion forces
69
The hybridization of the central carbon in CH3C≡N and the bond angle CCN are
a) sp2, 180°.
b) sp, 180°.
c) sp2, 120°.
d) sp3, 109°.
b) sp, 180°.
70
The correct geometry around oxygen in CH3OCH3 is
a) linear.
b) bent.
c) tetrahedral.
d) trigonal planar
b) bent.
71
Another name for tetrachloromethane
a) Chloroform
b) Carbon Tetrachloride
c) Freon
d) Chloromethane
b) Carbon Tetrachloride
72
The general formula for an ester is
a) ROR’
b) RCOOH
c) RCOR’
d) RCOOR’
d) RCOOR’
73
Rank the following compounds in the order of increasing basicity:
I. p-nitroaniline III. N-methylaniline
II. p-aminobenzaldehyde IV. p-methylaniline
a) I, II, III, IV
b) IV, III, II, I
c) I, II, IV, III
d) III, IV, I, II
c) I, II, IV, III
74
Aldehydes and ketones generally react by
a) nucleophilic addition
b) electrophilic addition
c) nucleophilic substitution
d) electrophilic substitution
a) nucleophilic addition
75
The most acidic phenolic compound:
a) p-chlorophenol
b) 2,4-dichlorophenol
c) 2,4,6-trichlorophenol
d) Phenol
c) 2,4,6-trichlorophenol
76
Which of the following has the lowest boiling point?
a) CH3COCH3
b) CH3OCH3
c) CH3COOH
d) CH3CHO
b) CH3OCH3
77
Which of the following has the lowest boiling point?
a) o-hydroxynitrobenzene
b) p-hydroxynitrobenzene
c) m-hydroxynitrobenzene
d) p-hydroxybenzoyl chloride
a) o-hydroxynitrobenzene
78
Which of the following properties indicates very strong intermolecular forces in liquids?
a) very low surface tension
b) very low boiling point
c) very low critical temperature
d) very low vapor pressure
d) very low vapor pressure
A very low vapor pressure indicates that the liquid has strong intermolecular forces. This is because strong intermolecular forces make it difficult for molecules to escape into the gas phase, resulting in fewer molecules in the vapor phase and thus lower vapor pressure.
79
Which pair of functional group and characteristic reaction type are NOT a match?
a) Alkane, Radical Substitution
b) Alkyl halide, Nucleophilic Substitution
c) Alkyne, Electrophilic Substitution
d) Carboxylic acid, Nucleophilic Acyl Substitution
c) Alkyne, Electrophilic Substitution
80
Which would be the strongest acid?
a) CH3CH2CH2COOH
b) CH3CH2CH(F)COOH
c) CH3CH(F)CH2COOH
d) FCH3CH2CH2COOH
e) CH3CH2CH2CH2OH
b) CH3CH2CH(F)COOH
81
The reaction of sodium ethoxide with iodoethane to form diethyl ether is classified as ...
a) an electrophilic substitution
b) a nucleophilic substitution
c) a radical substitution
d) an electrophilic addition
b) a nucleophilic substitution
AHA ALE TA
82
Which one of the following alcohols will be oxidized by Jones' reagent (CrO3 in 50% sulfuric acid) to
a ketone having the same number of carbon atoms ?
a) 1-methylcyclohexanol
b) 3,3-dimethylcyclopentanol
c) 3-methyl-1-hexanol
d) 3-ethyl-3-hexanol
b) 3,3-dimethylcyclopentanol
83
Which of the following reagents would be best for oxidizing a 1-alcohol to an aldehyde?
a) H3PO4
b) PCC in CH2Cl2
c) Jones' reagent (H2CrO4)
d) OsO4
b) PCC in CH2Cl2
84
Arrange according to increasing acidity
I. methanol II. phenol III. p-nitrophenol IV. p-methylphenol
a) I, II, III, IV
b) II, I, III, IV
c) I, II, IV, III
d) IV, III, I, II
c) I, II, IV, III
85
Arrange the following according to increasing acid strengths:
I. benzoic acid III. 4-cyanobenzoic acid
II. 4-methoxybenzoic acid IV. 4-methylbenzoic acid
a) II < III < I < II
b) IV < II < I < II
c) IV < II < III < I
d) III < I < II < IV
a) II < III < I < II
Lahi answer sa chatgpt
86
The solvent used for the preparation of Grignard reagent.
a) Alcohol
b) Ether
c) Acid
d) Ester
b) Ether
87
Predict the increasing order of reactivity by the SN2 mechanism:
CH3CH2−Cl
CH3−Cl
(CH3)2CH−Cl
CH3CH2CH2−Cl
(CH3)3C−Cl
a) V, IV, II, I, II
b) V, III, IV, I, II
c) V, III, IV, II, I
d) II, I, IV, III, V
b) V, III, IV, I, II
88
The enzyme that aids in the fermentation of sugar to alcohol.
a) Diastase c) Maltase
b) Zymase d) Glucosidase
b) Zymase
Diastase: Breaks down starch into maltose.
Maltase: Breaks down maltose into glucose.
Glucosidase: Hydrolyzes glycosidic bonds in carbohydrates.
89
Order the following set of compounds according to increasing rate of SN1 reactivity:
CH3CH2CH2 −Cl
H2C = CHCH2−C
(CH3)3C−Cl
CH3CH=CH−Cl
a) IV, I, II, III
b) I, IV, II, III
c) IV, I, III, II
d) III, II, I, IV
c) IV, I, III, II
90
A reaction of ester that will produce another ester.
a) Alcoholysis
b) Ammonolysis
c) Hydrolysis
d) Ozonolysis
a) Alcoholysis
Ammonolysis: A reaction where an amine reacts with an ester to produce an amide and an alcohol.
Hydrolysis: A reaction where an ester reacts with water to produce an alcohol and a carboxylic acid.
Ozonolysis: A reaction involving alkenes where ozone cleaves the double bonds to form carbonyl compounds, not related to esters.
91
The test for the presence of methyl carbonyl.
a) Benidect’s
b) Fehling’s
c) Haloforms
d) Tollen’s
c) Haloforms
Benedict’s test: Used to detect reducing sugars (like glucose).
Fehling’s test: Used to test for reducing sugars and aldehydes, especially those with free aldehyde groups.
Tollen’s test: Used primarily for the detection of aldehydes, particularly silver mirror formation.
92
An inorganic ester used as explosive.
a) ethyl nitrate
b) ethyl sulfate
c) pentyl nitrate
d) glyceryl trinitrate
d) glyceryl trinitrate
93
A reducing test that gives a brick red precipitate with aldehydes.
a) Benidect’s
b) Millon’s
c) Schiff’s
d) Tollen’s
a) Benidect’s
94
An exothermic reaction of alkanes
a) Combustion
b) Reduction
c) Pyrolysis
d) Hydrogenation
a) Combustion
95
Which of the alkanes below has the lowest boiling point
a) n-pentane
b) isopentane
c) neopentane
d) sec-pentane
c) neopentane
96
The aldehyde used as preservative.
a) Butanal
b) Propanal
c) Ethanal
d) Methanal
d) Methanal
97
The IUPAC name of the simplest ketone.
a) Butanone
b) Pentanone
c) Hexanone
d) Propanone
d) Propanone
98
Freon is an example of
a) hydrocarbon
b) alkyl halide
c) alcohol
d) aldehyde
b) alkyl halide
99
Rubbing alcohol is an example of
a) normal alcohol
b) primary alcohol
c) secondary alcohol
d) tertiary alcohol
c) secondary alcohol
"iso"-propyl alcohol `
100
The alcohol present in all drinking liquor.
a) Methyl alcohol
b) Ethyl alcohol
c) Isopropyl alcohol
d) Amyl alcohol
b) Ethyl alcohol
101
The number of structural formulas possible for the alkyne C6H10.
a) seven
b) six
c) four
d) five
a) seven
102
The acid responsible for the irritating sting of ants.
a) Formic acid
b) Acetic acid
c) Citric acid
d) Lactic acid
a) Formic acid
103
When proteins are broken down by enzymes, the products are:
a) amino acids
b) carbohydrates
c) fatty acids
d) nucleic acids
a) amino acids
104
Which of the following vitamins are all fat soluble.
a) ABCD
b) ACDE
c) ADEK
d) BCDE
c) ADEK
105
Deficiency of this vitamin will cause scurvy.
a) Vit A
b) Vit B
c) Vit C
d) Vit D
c) Vit C
106
The process of copying DNA molecule.
a) translation
b) reproduction
c) replication
d) transcription
c) replication
107
The preparation of alkyl halide that obeys Markovnikov’s rule.
a) Hydrogenation
b) Halogenation
c) Hydrohalogenation
d) Hydration
c) Hydrohalogenation
108
What is the best reagent to convert isopropyl alcohol to isopropyl bromide?
a) HBr
b) SOBr2
c) Br2
d) CH3MgBr
b) SOBr2
109
Which of the following statements is TRUE?
a) Tertiary-butyl free-radical intermediate is less stable than a methyl free-radical.
b) Anisole, C6H5-OCH3 is the same as para-methylphenol.
c) Phenol is hydroxycyclohexane.
d) 2-methyl-1,3-butadiene is also known as isoprene.
d) 2-methyl-1,3-butadiene is also known as isoprene.
a) Tertiary-butyl free-radical intermediate is less stable than a methyl free-radical.
False: A tertiary-butyl free radical is more stable than a methyl free radical due to greater hyperconjugation and inductive effects from surrounding carbon atoms.
b) Anisole, C₆H₅-OCH₃ is the same as para-methylphenol.
False: Anisole is an ether with the formula C₆H₅-OCH₃, while para-methylphenol (or p-cresol) has a hydroxyl group (–OH) instead of an ether group. They are not the same.
c) Phenol is hydroxycyclohexane.
False: Phenol is actually a benzene ring (C₆H₆) with a hydroxyl group (–OH) attached to it. Hydroxycyclohexane refers to a cyclohexane ring with an –OH group, which is a different compound.
d) 2-methyl-1,3-butadiene is also known as isoprene.
True: 2-Methyl-1,3-butadiene is indeed the IUPAC name for isoprene, a key building block in the production of natural rubber.
110
Compounds p-xylene & m-xylene are isomers of styrene.
True or False?
FALSE
p-Xylene and m-Xylene are not isomers of styrene; they are isomers of each other.
Isomers of styrene would include compounds that have the same molecular formula (C₈H₈) but different structures, such as ethylbenzene or 1,3-dimethylbenzene (which would correspond to m-xylene).
In summary, p-xylene and m-xylene are isomers of each other, but neither of them is an isomer of styrene.
111
Which of the following structural features is possessed by aldehydes but not by ketones?
a) At least one hydrogen atom is bonded to the carbonyl carbon atom.
b) At least one hydroxyl group is bonded to the carbonyl atom.
c) The carbonyl carbon atom is bonded to two other carbon atoms.
d) The carbonyl carbon atom is part of a ring structure.
a) At least one hydrogen atom is bonded to the carbonyl carbon atom.
112
Which of the following statements about oxidation of aldehydes and ketones is correct?
a) Aldehydes readily undergo oxidation, and ketones are resistant to oxidation.
b) Ketones readily undergo oxidation, and aldehydes are resistant to oxidation.
c) Both aldehydes and ketones readily undergo oxidation.
d) Both aldehydes and ketones are resistant to oxidation.
a) Aldehydes readily undergo oxidation, and ketones are resistant to oxidation.
113
What principal product would you expect from acid-catalyzed hydration of 2-methyl-1-butene?
a) 2-methyl-1-butanol
b) 3-methyl-2-butanol
c) 2-methyl-2-butanol
d) none, no reaction occurs
c) 2-methyl-2-butanol
114
This test reaction is chiefly important for the identification of aldehydes and ketones.
a) 2,4-DNP
b) Lucas
c) Baeyer’s
d) Tollen’s
a) 2,4-DNP
a) 2,4-DNP:
This reagent reacts with aldehydes and ketones to form 2,4-dinitrophenylhydrazones, which are typically bright yellow or orange precipitates. The formation of this precipitate is a clear indicator of the presence of carbonyl compounds (aldehydes or ketones).
b) Lucas Test:
This test is primarily used to differentiate between primary, secondary, and tertiary alcohols based on their reactivity with hydrochloric acid in the presence of zinc chloride. It is not specifically used for aldehydes and ketones.
c) Baeyer’s Test:
Also known as the permanganate test, this test is used for identifying alkenes and alkynes through the oxidation of double and triple bonds. While it can also oxidize aldehydes, it is not specific to aldehydes and ketones.
d) Tollen’s Test:
This test is specific for aldehydes and can differentiate them from ketones. It uses Tollen's reagent (silver nitrate in ammonia) to oxidize aldehydes, resulting in a silver mirror formation. However, it does not work for all ketones.
115
Esters of long–chain carboxylic acids and the trihydric alcohol, glycerol, are known as ________.
a) triacyglycerides
b) saccharides
c) amides
d) nucleotides
a) triacyglycerides
116
Upon treatment with H2SO4, a mixture of ethyl and n-propyl alcohols yields a mixture of three ethers.
These ethers are as follows except
a) ethyl ether
b) 1-ethoxypropane
c) 2-ethoxypropane
d) 1-propoxypropane
c) 2-ethoxypropane
117
Which carbonyl compounds have no alpha-hydrogen?
a) formaldehyde
b) ethanal
c) ethanol
d) acetone
a) formaldehyde
α-Hydrogens are the hydrogen atoms attached to the carbon atom adjacent to the carbonyl group (C=O).
Let's analyze each option:
a) Formaldehyde (HCHO):
Structure: H-C=O
Formaldehyde has no α-hydrogens because there is no carbon atom adjacent to the carbonyl carbon.
118
Classify the following amine: (CH3)3C-NH2
a) Primary Amine
b) Secondary Amine
c) Tertiary Amine
d) Quaternary Ammonium Salt
a) Primary Amine
