CBSE Class 12 Chemistry Halo Alkanes And Haloarene Worksheet

MCQ Questions for NCERT CBSE Class 12 Chemistry Halo Alkanes And Haloarene

Question. Which of the following has the highest nucleophilicity ?
(a) F-
(b) OH-
(c) CH3-
(d) NH2-

Answer: C

Question. The addition of propane with HOCl proceeds via the addition of
(a) H+ in the first step
(b) Cl+ in the first step
(c) OH- in the first step
(d) Cl+ and OH- in a single step

Answer: B

Question. Which of the following compound is allylic halide?
(a). 1- Chloropropane.
(b). 3- Chloropropene.
(c). 2- Chloropropene.
(d). 1-Chloropropene

Answer: B

Question. Aromatic nitrile (ArCN) are not prepared by the reaction:
(a) ArX. +KCN.
(b) Ar N₂+ + CuCN.
(c) Ar CONH2 + P2 O₅
(d) ArCONH₂ + SOCl₂

Answer: A

Question. In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti markownikov’s addition to alkenes because
(a) both are high ionic.
(b) one is oxidizing and the other is reducing
(c) one of the steps are exotheric in both the cases
(d) all the Steps are exotheric in both the reaction

Answer: C

Question. 1,1 Dicholopropane on hydrolysis gives
(a) propanone.
(b) propapnal
(c) ethanol
(d) 1,1-Propanediol

Answer: B

Question. Best reagent for preparing a cholroalkane from an alcohol is…….
(a) SOCl2.
(b) HCl/ZnCl2.
(c) PCl₃.
(d) Cl2/CCl4

Answer: A

Question. An SN₂ reaction at an asymmetric carbon of a compound always gives
(a) an a enantiomer of the substrate
(b) a of opposite optical rotation
(c) a mixture of diastereomers
(d) a single stereoisomer

Answer: D

Question. Molecules whose mirror image is non superimposable over them are known as chiral. Which of the following molecules are chiral in nature.
(a) 2-Bromobutane
(b)1-Bromobutane
(c) 2-Bromopropane
(d) 2-Bromobutane-2-ol

Answer: A , D

Question. Toluene reacts with a chlorine in the presence of iron (lll)chloride gives ortho and Para chloro compounds . The reaction is………..
(a) Electrphilic elimination reaction
(b) Electrophilic substitution reaction
(c) Free radical substitution reaction
(d) Nucleophilic substitution reaction

Answer: B

Question. The order of reactivity of the following alkyl halides for a SN2 reaction is
(a) RF>RCl > RBr >RI.
(b) RF> RBr >RCl >RI.
(c) RCl >RBr >RF. >RI.
(d). RI. >RBr. >RCl. >RF

Answer: D

Question. Which of the following represents a gem halide?
(a) Ethylene dichloride.
(b) 2.2 Dichroichloroprpane
(c) 1,3 Dichloropropane
(d) 1,2- Dicholoprpane

Answer: B

Question. Which of the following are the examples of vic – dihalide?
(a) Dichloromethane
(b) 1,2-dichloroethane
(c) Ethylidene chloride
(d)2,3-Dichloro butane

Answer: B , D

Question. Haloalkane contain halogen atom(s) attached to the sp2 hybridized carbon atom of an alkyd group . Identify Haloalkanes among the following compounds.
(a) 2-Bromopentane
(b) vinyl chloride
(c) Allyl chloride
(d) Chlorocyclohexane

Answer: A , C , D

Question. Which of the following statements are correct about the SN1 mechanism.
(a) reaction takes place via carbocation as the intermediate.
(b) The order of reactivity of various alkyl halide is 3°>2°>1°
(c) Inversion of configuration takes place
(d) The rate of the reaction depends upon the concentration of the nucleophile

Answer: A , B

Question. Which of the following compound don’t under go Nucleophilic substitution reaction easily?
(a) p-Chlorotoluene
(b) 3 -Chloropropene
(c) Benzyl chloride
(d) 2- Chloropentane

Answer: A , B

Question. The correct IUPAC name of the compound (C₂H₅)3CBr is……..
(a) 3- Bromo-3-ethylpentane
(b) 1-Bromo-3,3-diethylpropane
(c) 1 -Bromo -1,1,1-triethylmethane
(d) 1 Bromo-1,1-diethylpropane

Answer: A

Question. Which of the following statements are correct for ethylene dichloride and ethylidene chloride?
(a) There are structural isomers
(b) Both of these yield same product on reaction with alcoholic KOH solution
(c) both of these yield same product on treatment with aqueous KOH
(d) Both of these yield same product on reduction

Answer: A , B, D

Assertion Reason Based Question :

The following questions consist of two statements one labelled as Assertion A and other REASON R.
Examine both the statements carefully and mark the correct choice according to the instructions given below
(a) if both A and R are correct and R is the correct reason of A
(b) If both A and R are correct but R is not correct reason of A
(c) If A is correct R is wrong
(d) If A is wrong R is correct.

Question. ASSERTION A: Addition of halogen acids to alkenes takes place via carbocations as intermediates.
REASON R: HBr adds to propene more readily than ethereal.

Answer: B

Question. ASSERTION A :Benzyl chloride undergoes nucleophilic substitution much more readily than CH3Cl.
REASON R The intermediates Carbocation formed in case of substitution of Benzyl chloride is less stable than in case of CH3Cl.

Answer: C

Question. ASSERTION A : Among the isomeric dichlorobenzenes o- dichlorobenzene has the highest melting point.
REASON R: O -Dicholobenzene is the most polar among the isomeric dichlorobenzene

Answer: D

 One Mark Questions:

1. Give IUPAC name of the following organic compound:

CH3-CH=C- CH-CH3

CH3 Br

2. Write the structural formulae of 4-Chloropent-2-ene.

Q3.Arrange the following halides in order of increasing SN2 reactivity

CH3Cl,CH3Br,CH3CH2Cl, (CH3)2CHCl

Q5.What is the order of reactivity of different alkyl halides in nucleophilic substitution reaction?

Q4.An alkyl halide C4H9Cl is optically active. What is its structure?

Q7.Which type of solvents aregenerally used to carry out SN1 reaction?

Q8.Identify the chiral and achiral molecules in following pair of compounds?

A:CH3CHCH2CH3 B :CH3CH2CH2CH2Br

Br

Q9.Give two uses of iodoform (CHI3)?

Q10.Write a chemical reaction in which iodide ion displaces diazonium group from a diazonium salt?

Q11.How you will convert 2-Bromopropane to 1-bromopropane?

Q12.In following pairs of halogen compound which compound undergoes faster SN1 reaction?

A) Cl Cl iii) Cl iv)

i) ii) B)

Q13.How you will convert aniline into cholobenzene? Cl

Q14.Name the iodine containing hormone, the deficiency of which causes goiter?

Q15.Name the synthetic halogen compound which is used in treatment of malaria?

Q16.Which isomer of C4H9Br will have lowest boiling point?

Q17.Write the IUPAC name of DDT?

Q18.Why sulphuric acid is not used during reaction of alcohol with KI?

Q19.Out of CH3Br and CH3Cl which will have higher boiling point and why?

Q20.Which one of following has highest dipole moment?

(i) CH2Cl2 (ii) CHCl3 (iii) CCl4

 Two marks questions:

Q1.Define the following terms:

(i) Ambidient nucleophile (ii) Chirality

Q2.Write short note on sandmeyer reaction?

Q3.Write the structures of main products:

(i).Chlorination of benzene in presence of UV light.

(ii).Propene is treated with HBr in presence of benzoyl peroxide.

Q4.Complete the following reactions:

 (i).C6H5N2Cl +KI ?

(ii) CH2=CH2 +Br2 CCl4 ?

Q5.Explain why haloarenes are much less reactive than haloalkanes towards nucleophilic substitution

reaction?

Q6.Write short note on:

(i).Wurtz reaction

(ii).Wurtz-Fittig reaction.

Q7.How you will convert:

(i).Ethyl chloride into ethyl alcohol.

(ii).Ethyl chloride to ethane

Q8.Alkyl halides are insoluble in water though they contain polar C-X bond?

Q9.Give one test to distinguish between:

(i).Chloroform and carbontetrachloride

(ii).Methanol and ethanol.

Q10.Write short note on :

(i).Finkelstein reaction

(ii).Hundsdiecker reaction

 Three Marks Questions:

1.Explain why:

(a).Dipole moment of cholorobenzene is lower than cyclohexyl chloride.

(b).Grignard reagent should be prepared under anhydrous conditions?

(c).Chloroform is stored in dark Brown bottles?

Question. What happens when tert-butyl alcohol is treated with Cu / at 573 K.?
Answer :

Question. Arrange the following halides in order of increasing SN² reactivity :
CH₃ — Cl, CH₃ — Br, CH₃CH₂Cl, (CH₃)2 CHCl
Answer : (CH₃)₂ CHCl < CH₃CH₂Cl < CH₃Cl < CH₃Br.
(Hint : As the size of the alkyl group increases SN² reactivity decreases.)

Question. Alkyl halides, though polar, are immiscible with water. Why?
Answer : Alkyl halides cannot form H-bonds with water molecules and hence are insoluble in water

Question. Grignard reagents should be prepared under anhydrous conditions. Why?
Answer : Because Grignard reagents have a very strong affinity for H⁺ ions. In presence of water, they abstract H⁺ ions from water and form alkanes. To prevent this, they should be prepared under anhydrous conditions

Question. Which of the following two compounds would react faster by SN² pathway: 1-bromobutane (OR) 2-bromobutane.
Answer : The reactivity in SN² reaction depends upon the extent of steric hindrance. i-bromobutane is a 1° alkyl halide and 2-bromobutane is a 2° alkyl halide. Since there will be some steric hindrance in 2° alkyl halide than in 1° alkylhalide, therefore 1°-bromobutane will react faster than 2-bromobutane in SN² reaction.

Question. Allyl Chloride is more reactive than n-propyl Chloride towards nucleophilic substitution reactions. Explain.
Answer : Allyl Chloride readily undergoes ionization to produce resonance stabilized allyl carbocation. Since carbocations are reactive species they readily combine with OH^– ions to form allyl alcohol.

Question. Explain why is Chlorobenzene difficult to hydrolyse than ethyl chloride ?
Answer : The lone pair of electrons of Chlorine is Chlorbenzene participates into resonance with the benzene ring.As a result C — Cl bond acquires a partial double bond character. Therefore, this C — Cl bond is stronger than C — Cl bond in ethyl chloride which is a pure single bond. As such the Chlorobenzene is difficult to hydrolyse than ethyl chloride

Question. R—Cl is hydrolysed to R—OH slowly but the reaction is rapid if a catalytic amount of KI is added to the reaction mixture.Why?
Answer : Iodide ion is a powerful nucleophile and hence reacts rapidly with RCl to form RI.
KI ——— + + I^–; R — Cl + I^– ——— — I + Cl^–

Question. Why haloalkanes are more reactive than haloarenes.
Answer : In haloarenes, there is double bond character b/w carbon and halogen due to resonance effect which makes him less reactive.

Question. Why do haloalkenes undergo nucleophillic substitution whereas haloarenes under go electophillic substitution?
Answer : Due to more electro negative nature of halide atom in haloalkanes carbon atom becomes slightly positive and is easily attacked by nucleophillic reagents.
While in haloarenes due to resonance, carbon atom becomes slightly negative and attacked by electrophillic reagents.

Question. Aryl halides cannot be prepared by the action of sodium halide in the presence H₂SO₄ .Why?
Answer : Due to resonance the carbon- oxygen bond in phenols has partial double bond and it is stronger than carbon oxygen single bond.

Question. Why is Sulphuric acid not used during the reaction of alcohols with KI ?
Answer : It is because HI formed will get oxidized to I2 by concentrated Sulphuric acid which is an oxidizing agent

Question. p- dichlorobenzene has highest m.p. than those of ortho and m-isomers.?
Answer : p- dichlorobenzene is symmetrical, fits into crystal lattice more readily and has higher melting point.

Question. Although chlorine is an electron- withdrawing group, yet it is ortho and para directing in electrophillic aromatic substitution reactions.Why?
Answer : Chlorobenzene is resonance hybrid, there is –ve charge at 0 and para positions, electrophillic substitution reaction will take place at 0 and para position due to +R effect. +R effect is dominating over – I effect. .

Question. Explain why vinyl chloride is unreactive in nucleophillic substitution reaction?
Answer : Vinyl chloride is unreactive in nucleophillic substitution reaction because of double bond character between C = CL bond which is difficult to break

Question. Arrange the following compounds according to reactivity towards nucleophillic substitution reaction with reagents mentioned :-
a. 4- nitro chloro benzene, 2,4 di nitro chloro bemzene, 2,4,6, trinitrochlorobenzene with CH₃ONa
Answer : 2,4,6, trinitrochlorobenzene > 2,4 dinitrochlorobemzene > 4- nitrochlorobenzene

Question. Arrange in order of boiling points.
a. Bromobenzene, Bromoform, chloromethane,Dibromo-methane
b. 1-chloropropane, Isopropyle chloride, 1-Chlorobutane.
Answer : (a) chloromethane < Bromobenzene < Dibromo-methane < , Bromoform
(b) , Isopropyle chloride <1-chloropropane <1-Chlorobutane 3⁰ > 2⁰> 1⁰ (SN¹)

Question. Predict the reactivity in SN1
Answer : a. C₆H₅CH₂Br, C₆H₅CH (C₆H₅)Br, C₆H₅CH(CH₃)Br, C₆H₅C(CH₃)(C₆H₅)Br
C₆H₅C(CH₃)(C₆H₅)Br > C₆H₅(C₆H₅)Br > C₆H₅CH(CH₃)Br > C₆H₅CH₂Br
              (30)                         (20)                    (20)                 (10)

Question. Why is vinyl chloride less reactive than ethyl chloride?
Answer : Due to the sp2 hybridization and resonance in vinyl chloride.

Question. Chloroform is stored in dark coloured & sealed bottle. Why?
Answer : Because it undergoes oxidation and converting to poisonous gas phosgene

2 MARK QUESTIONS

Question. The treatment of alkyl chlorides with aqueous KOH lead to the formation of alcohols but in presence of alcoholic KOH alkenes are major products. Explain?
Answer : In aqueous KOH,OH- is nucleophile which replaces another nucleophile.
R-X +KOH R-OH +KX
Where as in alcoholic KOH
C₂H₅OH +KOH → C₂H₅O- + K⁺
CH₃CH₂^-Cl + alcoholic KOH--------→ CH₂ =CH₂ + C₂H₅OH
(C₂H₅O_-)

Question. p-Dichlorbenzene has higher melting point and lower solubility than those of o- and m- isomers. Discuss.
Answer : The p-isomer being more symmetrical fits closely in the crystal lattice and thus has stronger
intermolecular forces of attraction than those of o- and m- isomers. Since during melting or dissolution, the crystal lattice breaks, therefore a larger amount of energy is needed to melt or dissolve the p- isomer than the corresponding o- and meta isomers.

Question. Haloalkanes react with KCN to form alkyl cyanides as major product while AgCN form isocyanide as the chief product. Explain
Answer : KCN is a ionic compound and provides cyanide ions in solution. Although both carbon and nitrogen atoms are in a position to donate electron pairs, the attack takes place mainly through Carbon atom and not through nitrogen atom since C — C bond is more stable than C — N bond. However AgCN is mainly covalent in nature and nitrogen is free to donate electron pair forming isocyanide as the main product.

Question. Explain why is Chlorobenzene difficult to hydrolyse than ethyl chloride ?
Answer : The lone pair of electrons of Chlorine is Chlorbenzene participates into resonance with the benzene ring.
As a result C — Cl bond acquires a partial double bond character. Therefore, this C — Cl bond is stronger than C — Cl bond in ethyl chloride which is a pure single bond. As such the Chlorobenzene is difficult to hydrolyse than ethyl chloride

Question. Which compound will react faster in SN² reaction with OH---?
a. CH₃Br and CH₃I (SN²)
b. (CH₃)₃C-Cl or CH₃Cl (SN²)
Answer : a) CH₃I will react faster than CH₃Br
b) CH₃Cl will react faster than 30 halide

Question. Alcohols reacts with halogen acids to form haloalkenes but phenol does not form halobenzene. Explain
Answer : The C-O bond in phenol acquires partial double bond character due to resonance and hence be cleared by X- ions to form halobenzenes. But in alcohols a pure C — O bond is maintained and can be cleared by X–ions.

Question. How the following conversions can be carried out?
a. Propene to propan-1-ol
b. 1-Bromopropane to 2-bromopropane
Answer : a)

Question. The treatment of alkyl chlorides with aq KOH leads to the formation of alcohols but in presence of alcoholic KOH, alkenes are the major products. Explain.
Answer : In aq. solution, KOH is almost completely ionised to give OH^– ions which being a strong nucleophile brings about a substitution reaction to form alcohols. Further in aq. solution, OH– ions are highly solvated (hydrated).
This solution reduces the basic character of OH^– ions which fail to abstract a hydrogen from the -carbon of the alkyl halide to form an alkene.
However an alcoholic solution of KOH contains alkoxide (RO^–) ions which being a much stronger
base than OH^– ions preferentially abstracts a hydrogen from the -carbon of the alkyl halide to form alkene.

Question. Tert-butyl chloride reacts with aq. NaOH by SN¹ mechanism while n-butyl chloride reacts by SN² mechanism. Why ?
Answer : Tert-butyl chloride reacts via SN¹ mechanism because the heterolytic cleavage of C — Cl bond in tertbutyl chloride gives 3 carbocation which is highly stable and favourable for SN¹ mechanism.
Moreover, tert-butyl chloride (3°) bring a bulky molecule has steric hindrance which will not allow SN² mechanism to take place. Hence only SN1 mechanism can occur in tert-butyl chloride. However n-butyl chloride (1°) reacts via SN² because ‘C’ of C — Cl bond is less crowded and favourable for nucleophile to attack from back side results in the formation of transition state. It has less steric hindrance which is a favourable factor for SN² mechanism.

Question. Why alkyl halides are generally not prepared in laboratory by free radical halogenation of alkanes ?
Answer : It is because :
(i) It gives a mixture of isomeric monohalogenated products whose boiling points are so close
that they cannot be separated easily.
(ii) Polyhalogenation may also take place, thereby making the mixture more complex and hence
difficult to separate.

3 MARK QUESTIONS

Question. Haloalkanes undego nucleophilic substitutions whereas Haloarenes undegoes electrophilic substitutions.
Answer : Haloalkanes are more polar than haloarenes.
C-atom carrying the halogen in haloalkanes is mroe e– deficient than that in haloarenes.
Haloalkanes undergo nucleophilic substitution readily
In haloarenes, the love pair of electrons present on the halogen atom goes into resonance with the aryl ring. The aryl ring being rich in electron density, undergoes electrophilic substitutions.

Question. Why alkyl halides are generally not prepared in laboratory by free radical halogenation of alkanes?
Answer : It is because :
(i) It gives a mixture of isomeric monohalogenated products whose boiling points are so close
that they cannot be separated easily.
(ii) Polyhalogenation may also take place, thereby making the mixture more complex and hence
difficult to separate.

Question. Why preparation of aryl iodide by electrophilic substitution requires presence of an oxidising agent?
Why can aryl flouride not be prepared by this method?
Answer : Reactions with I2 are reversible in nature and require presence of oxidising agent (HNO₃, etc.) to oxidise HI formed during iodination and promote forward reaction.
Fluoro compounds cannot be prepared due to high reactivity of flourine.

Question. Why aryl halides are extremely less reactive towards nucleophilic substitution?
Answer : (i) Resonance effect :
Due to resonance C — Cl bond acquires partial double bond character.
(ii) Difference in hybridisation of Carbon in C —X bond : in haloarene C-atom attached to halogen in sp² hybrid while sp³ in haloalkane.
C — X bond length in sp² hybrid is shorter and hence stronger and difficult to break.
(iii) Instability of phenyl cation
(iv) Possible repulsion of nucleophile to approach e– rich arenes.

Question. (i) Arrange in order of property indicated :
CH₃CH₂CH₂CH₂Br, (CH₃)₃ Br, (CH₃)₃ CHCH₂ Br
(Increasing boiling point)
(ii) CH₃F, CH₃I, CH₃Cl, CH₃Br (nucleophilic substitution)
Answer : (i) B. P. decreases with increase in branching due to decrease in Van der Waals forces of attraction.
(CH₃)₃ CBr < (CH₃)₂ CHCH₂ Br < CH₃CH₂CH₂CH₂Br
(ii) Reactivity increases as C — X bond dissociation energy decreases.
CH₃F < CH₃Cl < CH₃Br < CH₃I

Question. Why does 2 bromopentane gives pent-2-ene as major product in elimination reaction ?
Answer :

This is because of Saytzeff’s rule — In dehydrohalogen reactions, the preferred product is that alkene which has the greater number of alkyl groups attached to the doubly bonded carbon atoms.

Question. Complete the reaction :
(a) CH₃OCH₃ + PCl₅ ———
(b) C₂H₅OCH₃ + HCl ———
(c) (C₂H₅)₂ O + HCl ———
Answer : (a) 2CH3Cl
(b) CH₃Cl + C₂H₅OH
(c) C₂H₅Cl + C₂H₅OH

Question. Distinguish between the following pair of organic compounds
i) CCl₄ and CHCI₃
ii) Chlorobenzene and Benzyl chloride
Answer : i) Carblamine reaction : chloroform gives offensive smell due to formation isocyanide but CCl₄ don’t.
ii) Diazotisation test will be given by benzyl chloride

Question. How are the following conversions carried out?
(i) Benzyl chloride → Benzyl alcohol. (ii) Ethyl magnesium chloride → Propan-1-ol.
Cu /HCl
(iii) C₆H₅N₂Cl ───────→
Answer : i) Hydrolysis with water.
ii) Nucleophillic addition with HCHO followed by hydrolysis.
iii)               Cu /HCl
C₆H₅N₂Cl ───────→C₆H₅Cl

Question. Write the formula of main product formed in the following chemical reactions.
Na
(i) (CH₃)₂ CH-C1 ──────→
                        Dry ether
                              Δ
(ii) CH₃Br + AgF──────→
                            Dry acetone
(iii) CH₃CH₂Br + Nal ───────→
Answer : (a) (CH₃)₂ CH-C1 ──────→ (CH₃)₂ CH-CH(CH₃)₂
                           Dry ether
                                 Δ
(b) CH₃Br + AgF──────→CH3F
                              Dry acetone
(c) CH₃CH₂Br + Nal ───────→ CH₃CH₂I

5 MARKS QUESTIONS

Question. Identify A, B, C, D, E, R, R¹ in the following 
Answer :

Question. a).p-dichlorobenzene has higher melting point and lower solubility than o- and m-isomer. Explain?
b) Which will have a higher boiling point?
1 - Chloro enthane or - 2 methyl -2- chlorobutane
Give reasons?
c) Chloroform is not used as anesthetic nowadays. Why?
Answer : a) The p-isomer being more symmetrical fits directly in the crystal lattice and thus has stronger inter molecular forces of attraction than o- and m- isomers.During melting or dissolution, the crystal lattice breaks. Therefore, a large amount of energy is needed to melt or dissolve the p-isomer than the resultant oand m- isomers.
b) 1-chloro pentane
Surface area and hence Van der Waal’s forces of attraction decreases on branching.
c) Due to the formation of poisonous gas during oxidation.

Question. (a) p - nitro chlorobenzene undergoes nucleophilic substitution faster than chlorobenzene. Explain giving the resonating structures as well.
(b)Allyl chloride is more reactive than n - propyl chloride towards nucleophilic substitution reaction. Explain why?
(c) Give IUPAC name of the following organic compound C₆H₅CH₂Cl 
Answer : (a) In this reaction a carbanion intermediate is formed. This is stabilized by Resonance in p-nitrochloro benzene Resonance Structure
(b) In allyl chloride, the carbocation formed is stabilised due to resonance while the carbocation formed form n - propyl chloride i.e. is less stable, so allyl chloride is more reactive towards nucleophilic substitution reaction.
(c) Chlorophenylmethane

Question. a) Why do alcohols have higher boiling points than the halo alkanes of the same molecular mass?
b) Convert the following:
i) Benzene to aniline.
ii) Benzene to diphenyl
iii) Benzene to p-Chloro toluene.
Answer : a) Alcohols are capable of forming intermolecular H-bonds .
b) i) C₆H₆ + Cl₂ -----------→ C₆H₅Cl + NH₃ ---------------→ C₆H₅NH₂ + HCl
       FeCl₃                            Cu₂O,Δ
ii) C₆H₆ + Cl₂ -----------→ C₆H₅Cl + 2Na + C₆H₅Cl ------------→ C₆H₅-C₆H₅ + 2NaCl
     FeCl₃                           Dry ether
iii) C₆H₆ + CH₃Cl ------------→ C₆H₅CH₃ + Cl₂ ------------------→ C⁶H₄CH₃Cl + HCl
     AlCl₃                                     FeCl₃