CBSE Questions for Class 12 Engineering Chemistry Haloalkanes And Haloarenes Quiz 3 - MCQExams.com

In Friedel craft alkylation of benzene with methyl chloride, the catalyst used is:
  • Anhydrous $$AlCl_{3}$$
  • Conc. sulphuric acid
  • Dilute sulphuric acid
  • Anhydrous $$ZnCl_{2}$$
Which of the following reagents, when heated with ethyl chloride, forms ethylene?
  • $$Aq.\ KOH$$
  • $$Zn/HCl$$
  • $$Alc.\ KOH$$
  • $$HI$$
Ethyl chloride is one of the reactants in:
  • Wurtz reaction
  • Williamson's synthesis
  • Friedel-craft's alkylation
  • All the above
Which of the following statements are true about $$CHCl_{3}$$?

i) It is used as an anesthetic agent.
ii) It is used as a solvent.
iii) It has $$sp^{2}$$ hybridized carbon.
iv) It has a distorted tetrahedral shape.

The correct statements are:
  • i, ii, iv
  • iii, iv
  • i, ii, iii
  • i, ii
$$S_{N}1$$ reaction is favoured by:
  • non-polar solvents
  • bulky group on the carbon atom attached to the halogen atom
  • small groups on the carbon atom attached to halogen atom
  • all the above
Identify the set of reagent/reaction conditions 'X' and 'Y' in the following set product:

$$CH_3-CH_2-CH_2Br\xrightarrow{\text{X}}CH_3-CH=CH_2  \xrightarrow{\text{Y}}CH_3-\underset{|}CH-CH_3$$
                                                                                                    $$Br$$
  • $$X=$$  dilute aqueous NaOH $$20 ^ { \circ } \mathrm { C }; \mathrm { Y }=$$ HBr/acetic acid $$20 ^ { \circ } C$$
  • $$X=$$ concentrated alcoholic $$\mathrm { NaOH } , 80 ^ { \circ } \mathrm { C } ; \mathrm { Y }=$$ HBr/acetic acid $$20 ^ { \circ } C$$
  • $$X=$$  dilute aqueous NaOH $$20 ^ { \circ } \mathrm { C };$$ $$\mathrm Y=\mathrm { Br } _ { 2 } / \mathrm { CHCl } _ { 3, } \ 0 ^ { \circ } \mathrm { C }$$
  • $$X=$$ concentrated alcoholic $$\mathrm { NaOH } , 80 ^ { \circ } \mathrm { C } ; \mathrm { Y }=$$ $$\mathrm { Br } _ { 2 } / \mathrm { CHCl } _ { 3 } , 0 ^ { \circ } \mathrm { C }$$
On reaction with benzene, which halide is least reactive for  Friedel crafts reaction ? 
  • Isopropylchloride
  • Vinyl chloride
  • Benzylchloride
  • methylchloride
$$CH\equiv CH\overset{H_2O/Hg^{2+}}{\underset{H_2SO_4}{\rightarrow}} X \overset{LiAlH_4}{\rightarrow} Y \overset{P_4/Br_2}{\rightarrow} Z$$ where Z is:
  • Ethylene bromide
  • Ethanol
  • Ethyl bromide
  • Ethylidene bromide
The product of the following reaction 
$$ C_6H_5Cl \xrightarrow [(Room\  temp.)]{KOH(aq)} product $$
  • $$ C_6H_5OH $$
  • $$ C_6H_4(OH)Cl$$
  • $$ C_6H_4(OH)_2 $$
  • No reaction
Interhalogen wwhich is very unstable among the following >
  • BrCi
  • ICI
  • IF
  • IBr
The order of decreasing reactivities of these alcohols towards nucleophilic substitution with $$HBr$$ is:
1581113_26d4048cd26f4f58bba1f9a72b90621f.PNG
  • $$III> I> IV> II$$
  • $$III> I> II> IV$$
  • $$I> III> IV> II$$
  • $$I> III> II> IV$$
Which of the following cannot shows $$S_{N}1$$ reaction?
2-Bromopentane is heated wtih potassium ethoxide in ethanol. The major product is:
  • trans-2-pentene
  • 2-ethoxypentane
  • 1-pentane
  • cis-2-pentene
In which of the following reaction $$ 1^o$$ alkyl halide is a major product ?
  • $$ { CH }_{ 3 }-\overset { \underset { | }{ H } }{ \underset { \overset { | }{ { CH }_{ 3 } } }{ C } } -Ph\xrightarrow [ ]{ { Cl }_{ 2 }/hv } Product $$
  • $$ { CH }_{ 3 }-\underset { \underset { { CH }_{ 3 } }{ | } }{ CH } -CH_{ 3 }\xrightarrow [ ]{ { Br }_{ 2 }/hv+\Delta } Product $$
  • $$ { CH }_{ 3 }-\underset { \underset { { CH }_{ 3 } }{ | } }{ CH } -CH_{ 3 }\xrightarrow [ ]{ { Cl }_{ 2 }/hv } Product $$
  • $$ { CH }_{ 3 }-\underset { \underset { { CH }_{ 3 } }{ | } }{ CH } -CH=CH_{ 2 }\xrightarrow [ ]{ { Cl }_{ 2 }/hv+\Delta } Product $$
The major product of the following reaction is:
1614288_d51fde05a09c44dd9709785a4125833a.png
Which one of the following is likely to give a precipitate with $$AgNO_3$$ solution?
  • $$(CH_3)_3CCl$$
  • $$CHCl_3$$
  • $$CH_2=CH-Cl$$
  • $$CCl_4$$
Which of the following factors does not favour $$S_{N}1$$ mechanism?
  • Strong nucleophile
  • Polar solvent
  • Low conc. of nucleophile
  • $$3^{0}$$ halide
$$C - Cl$$ bond of chlorobenzene in comparison to $$C - Cl$$ bond of methyl chloride is:
  • longer and weaker
  • shorter and weaker
  • shorter and stronger
  • longer and stronger
The reaction conditions leading to the best yield of $$C_{2}H_{5}Cl$$ are:
  • $$C_{2}H_{6}(excess)+Cl_{2}\rightarrow $$
  • $$C_{2}H_{6}+Cl_{2}\rightarrow $$
  • $$C_{2}H_{6}+Cl_{2}(excess)\rightarrow $$
  • none of these
The IUPAC name of chloretone is :
  • Trichloroacetone.
  • Trichloronitromethane.
  • 1,1,1-Trichloro-2-methyl-2-propanone.
  • 1,1,1-Trichloro-2-methyl-2-propanol.

Product is :

137086_b6cbf35bf69c4a2dbc5f73f67f26f801.png
Select the correct statement:
  • 1,4-dibromobutane react with excess of magnesium in ether to generate di-Grignard reagent.
  • 1,2-dichlorocyclohexane treated with excess of Mg in ether produces cyclohexene.
  • Vicinal dihalides undergo dehalogenation to give alkene when heated with Zn dust or Mg.
  • 1,3-dichloropropane by treatment with Zn dust or Mg forms cyclopropane.
Find out the incorrect statement.
129201_7f1dde53f43d47abb92cf1e1acffd108.png
  • It gives total 9 allylic brominated products
  • All allylic brominated products are optically active
  • Substrate has 7 allylic hydrogens
  • NBS gives Br constantly to reaction mixture.
Identify the product $$X$$.
129298_15768ce92ad649bdbfa6be2732e2959f.png
 Predict the product formed in the reaction.
129297_de39ae09b90547c3844bd9f5ebf3c132.png
$$X\xrightarrow{Na + dry\hspace{1mm}ether}Z$$
What can be used as $$X$$ if $$Z$$ is$$\displaystyle \:CH_{3}-CH_{3}$$? 
  • $$CH_{3}-Cl$$
  • $$HCHO$$
  • $$CH_3CHO$$
Select the incorrect statement about the product mixture in the following reaction.
129323.png
  • It is optically active.
  • It is racemic mixture.
  • It is a resolvable mixture.
  • It is a mixture of erythro compounds.
Which will give white ppt. with $$AgNO_{3}$$?
  • Both A and C
Assertion : Rate of ethanolysis of $$1^o$$ halide by $$S_N1$$ mechanism is fast.
Reason : Carbocation is stabilised by resonance.
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Assertion is incorrect but Reason is correct
  • Both Assertion and Reason are incorrect
Neopentyl chloride on reaction with ethanolic $$KOH$$ is likely to:
  • Neopentyl alcohol
  • Pentylene
  • $$2$$-Methyl-$$2$$-butene
  • Undergo no reaction
Which of the following reactions is not stereospecific?
  • $${S_N}{2}$$
  • Addition of $${Br}_{2}$$ to ethylene in $$C{Cl}_{4}$$
  • Electrophilic substitution
  • Glycol formation from alkenes with alkaline $$KMn{O}_{4}$$
In the reaction of p-chlorotoluene with $$K{NH}_{2}$$ in liquid $${NH}_{3}$$, the major product is:
  • o-toluidine
  • m-toluidine
  • p-toluidine
  • p-chloroaniline
$$1$$-Chlorobutane on reaction with alcoholic potash gives:
  • $$1$$-Butene
  • $$1$$-Butanol
  • $$2$$-Butene
  • $$2$$-Butanol
The reaction of $$t$$-butyl bromide with sodium methoxide mainly produces:
  • isobutane
  • isobutylene
  • $$t$$-butyl methyl ether
  • sodium tert-butoxide
$$n$$-Propyl bromide on treatment with ethanolic potassium hydroxide produces:
  • propane
  • propene
  • propyne
  • propanol
Structural isomerism and stereoisomerism should be considered when answering this question. 
$$2$$-bromopentane is heated with an excess of ethanolic sodium hydroxide. How many different hydrocarbons are produced?
  • $$1$$
  • $$2$$
  • $$3$$
  • $$4$$
When hydrochloric acid gas is treated with propene in the presence of benzoyl peroxide, it gives:
  • 2-chloropropane
  • allyl chloride
  • no reaction
  • n-propyl chloride
Which of the following is potential energy diagram for $$S_N1$$ reaction ?
What are the suitable reactant for the following ether synthesis?
$$CH_3 - \underset{CH_3\!\!\!\!}{\underset{|}{\overset{CH_3\!\!\!\!\!\!}{\overset{|}{C}}}} - O-CH_2-Ph$$
  • $$CH_3 - \underset{CH_3\!\!\!\!}{\underset{|}{\overset{CH_3\!\!\!\!\!\!}{\overset{|}{C}}}} - \bar{O} \overset{\oplus}{N}a +Ph - CH_2 - Cl$$
  • $$Ph - \underset{\!\!\!\!\!Cl}{\underset{\!\!\!\!\!|}{CH}} - CH_2 - CH_3 + CH_3 - \overset{\bar{O}\, \overset{\oplus}{N}a\!\!}{\overset{\!\!\!\!\!\!|}{CH}} - CH_3$$
  • $$CH_3 - \underset{CH_3\!\!\!\!}{\underset{|}{\overset{CH_3\!\!\!\!\!\!}{\overset{|}{C}}}} - Cl+PhCH_2\overset{\ominus}{O} \overset{\oplus}{N}a$$
  • $$CH_3 - \underset{CH_3\!\!\!\!}{\underset{|}{\overset{CH_3\!\!\!\!\!\!}{\overset{|}{C}}}} - \bar{O} \overset{\oplus}{N} a + CH_3 - Cl$$
Which of the following are correct for $$ S N^1 $$ reaction? 
  • The reaction intermediate is carbocation
  • In this reaction the complete inversion takes place
  • It is favoured by stability of carbocation
  • None of these
An enantiomerically pure acid is treated with racemic mixture of an alcohol having one chiral carbon. The ester formed will be:
  • Optically active mixture
  • Pure enantiomer
  • Meso-compound
  • Racemic mixture
An alkyl chloride produces a single alkene on reaction with sodium ethoxide and ethanol. The alkene further undergoes hydrogenation to yield 2-methylbutane. Identify the alkyl chloride from amongst the follwoing
  • $$ClCH_2CH(CH_3)CH_2CH_3$$
  • $$ClCH_2CH_2CH_2CH_3$$
  • $$ClCH_2CH(CH_3)CH_2CH_3$$
  • $$CH_3C(Cl)(CH_3)CH_2CH_3$$
The IUPAC name of the compound is 
1875279_74688e03512a4433ac2a7a914a2e815b.png
  • trans $$-3-$$ iodo $$-4-$$ chloro $$-3-$$ pentene
  • cis $$-2-$$ chloro $$-3-$$ iodo $$-2-$$ pentene
  • trans $$-2-$$ chloro $$-3-$$ iodo $$-2-$$ pentene
  • cis $$-3-$$ iodo $$-4-$$ chloro $$-3-$$ pentene
Cholorobenzene on treatment with sodium in dry ether gives diphenyl. The name of the reaction is
  • Fitting reaction
  • Wurtz - Fitting reaction
  • Sandmeyer reaction
  • Gattermann reaction
Which of the following will be the major and minor product?
1848140_130740811b544a20a87e08bcb644ea26.PNG
  • (A) is major product and (B) is minor products.
  • (A) is minor product and (B) is major product
  • Both (A) and (B) are major products.
  • Only (B) is formed and (A) is not formed.
Which of the following reactions will yield $$2,2-$$dibromopropane?
  • $$CH_2=CHBr+HBr$$
  • $$CH_3C \equiv CCH_3+2 HBr$$
  • $$CH_3C \equiv CH+2 HBr$$
  • $$CH_3CH = CHBr+HBr$$
State True or False:
The formation of $$CH_{3}Cl$$ by the gas phase ultraviolet irradiation of a mixture of $$CH_{4}$$ and $$Cl_{2} $$ involves free radical intermediate.
  • True
  • False
$$S{_N}{1}$$ reaction on optically active substrates mainly gives:
  • retention in configuration
  • inversion in configuration
  • racemic product
  • no product
Aryl halide is less reactive than alkyl halide towards nucleophilic substitution because:
  • of less stable carbonium ion
  • due to large $$C-Cl$$ bond energy
  • of inductive effect
  • of resonance stabilization and $$s{p}^{2}$$ hybridization of $$C$$ attached to halide
Which of the following alkyl halides will undergo $${S}_{N}{1}$$ reaction most readily?
  • $${ \left( C{ H }_{ 3 } \right) }_{ 3 }C-F$$
  • $${ \left( C{ H }_{ 3 } \right) }_{ 3 }C-Cl$$
  • $${ \left( C{ H }_{ 3 } \right) }_{ 3 }C-Br$$
  • $${ \left( C{ H }_{ 3 } \right) }_{ 3 }C-I$$
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