Haloalkanes and Haloarenes
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Nomenclature and nature of C-X bond
SubtopicNomenclature and nature of C-X bond under Haloalkanes and Haloarenes for Grade 12 ICSE.
Preview questions (no answers)
- 1.
What is the correct IUPAC name of the haloalkane represented in the provided diagram?
A.1,2-dichlorobutane
B.2,3-dichloropropane
C.1,2-dichloropropane
D.1,1-dichloropropane
- 2.
In the IUPAC system, haloalkanes are named as derivatives of:
A.Halogens
B.Alkanes
C.Alkenes
D.Alkynes
- 3.
What is the IUPAC name of the compound ?
A.Methyl bromide
B.Bromomethane
C.Bromoethane
D.Methane bromide
- 4.
Which halogen atom results in the most polar bond due to its electronegativity?
A.Chlorine
B.Bromine
C.Fluorine
D.Iodine
- 5.
What is the IUPAC name for ?
A.1,1-Dichloroethane
B.1,2-Dichloroethane
C.Ethylidene chloride
D.Dichloroethane
- 6.
The systematic IUPAC name for the compound is:
A.Chloroethene
B.Vinyl chloride
C.1-Chloroethene
D.Chloroethylene
- 7.
Identify the number of primary, secondary, and tertiary carbons in isobutyl bromide.
A.2 primary, 1 secondary, 1 tertiary
B.2 primary, 1 tertiary, 0 secondary
C.3 primary, 1 tertiary, 0 secondary
D.1 primary, 2 secondary, 1 tertiary
- 8.
Considering the nature of the bond, how does the replacement of all hydrogen atoms in methyl chloride () with fluorine atoms to form trifluoromethyl chloride () affect the physical properties of the bond?
A.The bond becomes longer because the bulky fluorine atoms increase the steric repulsion around the carbon center.
B.The bond becomes more polar because the fluorine atoms increase the overall molecular dipole moment through their collective inductive effect.
C.The bond becomes shorter and stronger because the highly electronegative fluorine atoms increase the partial positive charge on carbon, causing orbital contraction.
D.The bond becomes weaker because the fluorine atoms withdraw electron density, reducing the overlap between the carbon and chlorine orbitals.
- 9.
The IUPAC name of the compound is:
A.2-chloro-3-fluorobutane
B.3-chloro-2-fluorobutane
C.2-fluoro-3-chlorobutane
D.Both A and B are equivalent
- 10.
The effect of the halogen atom on the benzene ring in chlorobenzene is:
A.Deactivating and ortho-para directing
B.Activating and ortho-para directing
C.Deactivating and meta directing
D.Activating and meta directing
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Methods of preparation
SubtopicMethods of preparation under Haloalkanes and Haloarenes for Grade 12 ICSE.
Preview questions (no answers)
- 1.
Diazotization of aniline is carried out at which temperature range?
A.100 - 110
B.273 - 278
C.373 - 378
D.500 - 600
- 2.
Which of the following reagents will convert ethanol into ethyl chloride most effectively in terms of purification?
A.gas
B.C.D. - 3.
The addition of to trans-but-2-ene results in a product that is:
A.A meso compound
B.A racemic mixture
C.Optically active
D.A primary halide
- 4.
In the electrophilic substitution of benzene to form chlorobenzene, what species acts as the electrophile?
A.B.C.D. - 5.
Based on the reaction pathways shown in the diagram, identify the major organic products X and Y. Consider the specific conditions under which the Kharasch (peroxide) effect is applicable.
A.X is 1-chloropropane, Y is 1-bromopropane
B.X is 2-chloropropane, Y is 2-bromopropane
C.X is 2-chloropropane, Y is 1-bromopropane
D.X is 1-chloropropane, Y is 2-bromopropane
- 6.
Which reagent is most suitable for converting cyclohexanol to chlorocyclohexane?
A.at room temperature
B.and pyridine
C.in water
D.in sunlight
- 7.
The conversion of vinyl chloride to 1,1-dichloroethane can be achieved by adding:
A.B.C.D. - 8.
Which product is formed when naphthalene is treated with in the presence of ?
A.1-bromonaphthalene
B.2-bromonaphthalene
C.1,2-dibromonaphthalene
D.1,4-dibromonaphthalene
- 9.
A vicinal dihalide can be prepared from an alkene by:
A.Addition of
B.Addition of in
C.Reaction with
D.Reaction with
- 10.
Identify the reagent that can convert an alcohol directly to an alkyl iodide in one step.
A.B.(generated from and )
C.D.
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Physical and chemical properties
SubtopicPhysical and chemical properties under Haloalkanes and Haloarenes for Grade 12 ICSE.
Preview questions (no answers)
- 1.
When methyl chloride is treated with an excess of ammonia, the major product formed is:
A.Methylamine
B.Dimethylamine
C.Trimethylamine
D.Tetramethylammonium chloride
- 2.
Which of the following reacts fastest with to form an alkyl bromide?
A.Methanol
B.Ethanol
C.Propan-2-ol
D.2-methylpropan-2-ol
- 3.
The process of separating a racemic mixture into its pure enantiomers is known as:
A.Racemization
B.Resolution
C.Inversion
D.Retention
- 4.
In reactions, which solvent is generally preferred?
A.Polar protic solvents (like water)
B.Polar aprotic solvents (like acetone)
C.Non-polar solvents (like benzene)
D.Strong acids
- 5.
In the following reaction sequence, identify the final organic product 'Product Z':
A.n-Hexane
B.2,3-Dimethylbutane
C.n-Butane
D.Propane
- 6.
Why are alkyl halides insoluble in water despite being polar?
A.They cannot form hydrogen bonds with water molecules
B.They are heavier than water
C.They react with water to form alcohols immediately
D.The bond is too strong to break
- 7.
Which of the following compounds is the most stable carbocation intermediate in reactions?
A.B.C.D. - 8.
The reactivity of aryl halides towards nucleophilic substitution is increased by the presence of:
A.Electron withdrawing groups at ortho and para positions
B.Electron donating groups at ortho and para positions
C.Electron withdrawing groups at meta positions
D.Alkyl groups at any position
- 9.
Which of the following reagents is used to distinguish between chlorobenzene and benzyl chloride?
A.Aqueous followed by
B.Aqueous
C.Cold concentrated
D.Lucas reagent
- 10.
Identify the product 'C' in the following sequence: .
A.Chlorobenzene
B.Benzene
C.Monodeuterobenzene
D.Phenol
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Mechanism of substitution reactions (SN1 and SN2)
SubtopicMechanism of substitution reactions (SN1 and SN2) under Haloalkanes and Haloarenes for Grade 12 ICSE.
Preview questions (no answers)
- 1.
In the following flowchart representing a nucleophilic substitution reaction, identify the chemical species that functions specifically as the 'substrate'.
A.B.C.D. - 2.
In a haloalkane (), the carbon-halogen bond is polarized due to the difference in electronegativity. Based on the partial charges shown in the diagram, which atom acts as the electrophilic center that is targeted by an incoming nucleophile?
A.The Carbon atom
B.The Halogen atom
C.The Hydrogen atom
D.The entire group
- 3.
In the mechanism, the rate of reaction is fastest when the leaving group is attached to a:
A.Primary carbon
B.Secondary carbon
C.Tertiary carbon
D.Methyl carbon
- 4.
Which of the following is a nucleophile?
A.B.C.D. - 5.
The nucleophilic substitution of -trinitrochlorobenzene with water occurs:
A.Only at very high temperatures
B.By warming with water
C.By using and atm pressure
D.It does not occur at all
- 6.
In the reaction of alkyl halides with , the bond is formed because:
A.Carbon is more electronegative than nitrogen
B.The bond is more stable than the bond
C.Cyanide ion acts as a monodentate ligand
D.Potassium is a metal
- 7.
Aryl halides are less reactive towards nucleophilic substitution than alkyl halides due to:
A.The hybridized carbon of bond
B.The resonance effect
C.The instability of phenyl cation
D.All of the above
- 8.
Which of the following statements about the transition state is FALSE?
A.The central carbon atom is roughly hybridized.
B.The nucleophile and leaving group are at to each other.
C.The bond between the carbon and the nucleophile is fully formed.
D.The transition state has a pentacoordinate carbon atom.
- 9.
In the reaction: . If is a secondary alkyl group, and the solvent is acetone/ water, the rate law is found to be . This suggests:
A.The reaction is purely .
B.The reaction is purely .
C.Both and mechanisms are occurring simultaneously.
D.The reaction is .
- 10.
What is the role of in the reaction of alkyl halides?
A.It acts as a nucleophile.
B.It assists the departure of the leaving group by forming an insoluble silver halide precipitate.
C.It stabilizes the transition state of the reaction.
D.It acts as a catalyst for elimination.
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Optical rotation
SubtopicOptical rotation under Haloalkanes and Haloarenes for Grade 12 ICSE.
Preview questions (no answers)
- 1.
The rotation produced by a solution is observed to be for a path length of 1 dm. If the path length is increased to 2 dm, the observed rotation will be:
A.B.C.D. - 2.
Nicol prism is made of which crystal?
A.Quartz
B.Calcite
C.Mica
D.Diamond
- 3.
Which of these molecules is chiral?
A.Propane
B.1-Bromobutane
C.2-Bromobutane
D.2-Bromopropane
- 4.
The prefix 'dl' or '±' before a compound's name indicates:
A.A pure dextro isomer
B.A pure laevo isomer
C.A racemic mixture
D.A meso compound
- 5.
A sample of a haloalkane consists of a mixture of and enantiomers. Based on the composition shown in the diagram, if the specific rotation of the pure enantiomer is , what will be the observed specific rotation of the mixture?
A.B.C.D. - 6.
In a polarimetry experiment, a student measures the rotation of a chiral haloalkane. The experimental setup undergoes the changes illustrated in the diagram. If the initial observed rotation was , what is the final observed rotation ?
A.B.C.D. - 7.
If a sample rotates light by in a tube, what will be the rotation in a tube of the same solution?
A.B.C.D. - 8.
An optically active alkyl halide reacts with to give . on hydrolysis gives an acid . If is also optically active, which of the following is most likely ?
A.2-chlorobutane
B.1-chloro-2-methylpropane
C.2-chloro-2-methylbutane
D.Chlorocyclohexane
- 9.
Which of the following pairs represent diastereomers?
A.(R)-2-chlorobutane and (S)-2-chlorobutane
B.(2R, 3R)-2,3-dichloropentane and (2S, 3S)-2,3-dichloropentane
C.(2R, 3R)-2,3-dichloropentane and (2R, 3S)-2,3-dichloropentane
D.Meso-tartaric acid and its mirror image
- 10.
For a substance with , what does the subscript 'D' signify?
A.The D-configuration in the D/L system
B.The use of the D-line of the sodium lamp (589 nm)
C.Dextrorotatory nature
D.The density of the sample
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Reactions of haloarenes
SubtopicReactions of haloarenes under Haloalkanes and Haloarenes for Grade 12 ICSE.
Preview questions (no answers)
- 1.
Which of the following halogens is the most reactive in the Ullmann reaction?
A.Fluorine
B.Chlorine
C.Bromine
D.Iodine
- 2.
The Friedel-Crafts reaction of chlorobenzene with is known as:
A.Alkylation
B.Acylation
C.Sulphonation
D.Nitration
- 3.
Identify the compound formed in the Fittig reaction.
A.Diphenylmethane
B.Biphenyl
C.Naphthalene
D.Anthracene
- 4.
What type of reaction is the conversion of chlorobenzene to phenol using NaOH at high temperature and pressure?
A.Electrophilic substitution
B.Nucleophilic substitution
C.Free radical substitution
D.Elimination reaction
- 5.
Which of the following reagents is used in the nitration of chlorobenzene?
A.Dilute
B.Nitryl chloride
C.Concentrated + Concentrated
D.Liquid
- 6.
Chlorobenzene is less reactive than methyl chloride towards nucleophilic substitution. This is partly due to the fact that the bond in chlorobenzene has a bond order of:
A.1
B.Between 1 and 2
C.2
D.3
- 7.
Aryllithium compounds are prepared by the reaction of aryl halides with lithium in:
A.Alcohol
B.Water
C.Dry ether
D.Benzene
- 8.
Which statement is true regarding the Fittig reaction?
A.It involves the reaction of an aryl halide with an alkyl halide in the presence of sodium.
B.It involves the reaction of two molecules of aryl halide with sodium in dry ether to form biphenyl.
C.It requires a Lewis acid catalyst like .
D.It is used exclusively to prepare alkyl benzenes.
- 9.
In the reaction of chlorobenzene with chloral, which carbon of the chlorobenzene ring attaches to the chloral molecule?
A.The carbon at the meta position.
B.The carbon at the para position.
C.The carbon at the ortho position.
D.The carbon already carrying the chlorine atom.
- 10.
What is the product formed when chlorobenzene is treated with in the presence of pyridine at ?
A.Benzonitrile
B.Phenyl isocyanide
C.Chlorocyanobenzene
D.Aniline
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Polyhalogen compounds
SubtopicPolyhalogen compounds under Haloalkanes and Haloarenes for Grade 12 ICSE.
Preview questions (no answers)
- 1.
Which of the following is the formula for Chloropicrin?
A.B.C.D. - 2.
The use of as a dry cleaning agent has decreased because it causes damage to the:
A.Heart
B.Ozone layer
C.Fabric elasticity
D.Dye of the clothes
- 3.
Which polyhalogen compound can cause dizziness and nausea when its vapors are inhaled in moderate amounts?
A.Dichloromethane
B.Sodium chloride
C.Calcium carbonate
D.Magnesium sulfate
- 4.
Which of the following is true about DDT?
A.It is easily soluble in water
B.It is a highly effective fertilizer
C.It is very soluble in fats
D.It is a gaseous insecticide
- 5.
Which among the following polyhalogen compounds was historically used as the first effective insecticide, primarily to control malaria-carrying mosquitoes?
A.Chloroform
B.DDT
C.BHC
D.Carbon tetrachloride
- 6.
The compound 'Gammaxane' is which isomer of Benzene Hexachloride?
A.Alpha
B.Beta
C.Gamma
D.Delta
- 7.
Iodoform is a yellow solid. In which of the following solvents is it most soluble?
A.Water
B.Ethyl alcohol
C.Dilute
D.Aqueous
- 8.
Carbon tetrachloride is a non-polar molecule with a zero dipole moment. This is because:
A.The bonds are non-polar.
B.The electronegativity of and is identical.
C.The individual bond dipoles cancel out due to the symmetrical tetrahedral geometry.
D.It forms a giant covalent lattice structure like diamond.
- 9.
Which of the following statements regarding the stability of the trihalomethyl carbanions is CORRECT?
A.due to inductive effect.
B.due to back-bonding in .
C.All trihalomethyl carbanions are equally stable due to the hybridization.
D.because Iodine is the least electronegative.
- 10.
Freon-22 is commonly used in home air conditioners. What is its chemical formula?
A.B.C.D.
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