MCQ Questions for Class 12 Engineering Chemistry Haloalkanes And Haloarenes Quiz 2

Ethyl iodide and n-propyl iodide are allowed to undergo Wurtz reaction. The alkane which will not be obtained in this reaction is:

0%
butane
0%
propane
0%
pentane
0%
hexane

Explanation

$CH_3CH_2I+CH_3CH_2CH_2I$

(Wurtz reaction)

$\downarrow Na$

$\underset {butane}{CH_3CH_2CH_2CH_3}+\underset {hexane}{CH_3CH_2CH_2CH_2CH_2CH_3}+\underset {pentane}{CH_3CH_2CH_2CH_2CH_3}$

Ethyl iodide and n-propyl iodide are allowed to undergo Wurtz reaction and they form butane and hexane as self-addition products and pentane as cross addition product.

$\therefore$ So, propane will not be formed.

The Major products obtained when this substance is subjected to

${ E }_{ 2 }$ reaction will be:

0%
0%
0%
0%
both $1$ and $3$

Explanation

For

$E_{2}$ elimination, the hydrogen atom adjacent to the

$Cl$ atom needs to be in the opposite side of the ring.
1380470_1068143_ans_3dff588146e6450ebc0c03d221d58bc2.png

Given reaction is an example of Nucleophilic aromatic substitution. Which of the following halide

$(-X)$ is most readily replaced.

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$-F$
0%
$-Cl$
0%
$-Br$
0%
$-I$

Explanation

Flourine is readily replaced in nucleophilic aromatic substitution reaction as it has higher

$-I$ effect compared to other halogens.

$CH_3 - \underset{CH_3\!\!\!\!\!}{\underset{|}{\overset{CH_3\!\!\!\!\!}{\overset{|}{C}}}} - Br \xrightarrow[\Delta]{KOH (alcoholic)} (A) \xrightarrow{HBr/R_2O_2} \underset{(Major)}{(B)}$ Product

$B$ is:

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$CH_3 - \underset{H}{\underset{|}{\overset{\,\,\,\,\,CH_3}{\overset{|}{C}}}} - CH_2 - Br$
0%
$CH_3 - \underset{\,\,\,Br}{\underset{|}{\overset{\,\,\,\,\,CH_3}{\overset{|}{C}}}} - CH_3$
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$CH_3 - \underset{\,\,\,\,\,\,\,\,\,\,\,CH_2 - Br}{\underset{|\,}{\overset{\,\,\,\,\,\,CH_3}{\overset{|\,}{C}}}} - OH$
0%
$CH_3 - \underset{\,\,\,\,\,\,CH_3}{\underset{|}{\overset{\,\,\,\,\,\,\,\,\,\,\,\,CH_2 - H}{\overset{|}{C}}}}-Br$

Find out the major product.

The reaction of toluene with chlorine in the presence of light gives:

Which of the following alkyl halides will undergo

$S_N1$ reaction most readily?

0%
$(CH_3)_3C-F$
0%
$(CH_3)_3C-Cl$
0%
$(CH_3)_3C-Br$
0%
$(CH_3)_3C-I$

Explanation

All options given are alkyl halide (tertiary) so all will form tertiary carbocation.

But order of leaving group ability Is

$I^-$ >

$Br^-$ >

$Cl^-$ >

$F^-$

$S_{N}{1}$ mechanism goes through formation of carbocation.

More easily leaving group leaves more easily the carbocation will form.

Option D is correct.

Product D in the reaction is:

0%
optically active cyanide
0%
optically inactive cyanide
0%
optically active acid
0%
optically active aldehyde

In which of the following reactions, it proceeds via free radical mechanism?

0%
Halogenation of benzene
0%
Nitration of benzene
0%
Sulphonation of benzene
0%
Chlorination of toluene at high temperature

But-2-yne on chlorination gives:

0%
1-chlorobutabe
0%
1,2-dichlorobutabe
0%
1,1,2,2-tetrachloro butane
0%
2,2,3,3-tetrachloro butane

The product of reaction between chloroform and ethylamine in presence of alcoholic

$KOH$ is allowed to react with

$Cl_2$ .
The final product is:

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ethyl chloride
0%
ethylene dichloride
0%
ethyl iminocarbonyl chloride
0%
acetaldehyde

Which one of the following compound will be most reactive for

$S_N1$ reaction ?

Which of the compound gives a mixture of the substitution products on reaction with

$NaNH_{2}$ in liquid

$NH_{3}$ ?

Correct order of

$S_N1$ rate of the given compounds is:

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$I > II > III >IV$
0%
$II > I > IV > III$
0%
$I > IV > III > II$
0%
$III > IV > I > II$

Which of the following is most likely to show optical isomerism?

n-Propyl chloride and isopropyl chlordie mixture is subjected to the Wurtz reaction, which one of the following compounds is not formed.

0%
Hexane
0%
2,5-Dimethyl hexane
0%
2,3-Dimethyl butane
0%
2-Methyl pentane

Which is most reactive for

$SN^{1}$ reaction:-

The reaction of tertiary butyl bromide with sodium methoxide gives

0%
Isobutane
0%
Tertiary butyl methyl ether
0%
Isobutylene
0%
Butene

Identify the compound that give product on reaction with Zn dust and heat.

Which of the following compound give solvolysis reaction with slowest rate?

0%
$P-\overset { \oplus }{ N } { R }_{ 3 }-{ C }_{ 6 }{ H }_{ 4 }-C{ H }_{ 2 }-Br$
0%
$P-CCl_{3}-C_{6}H_{4}-CH_{2}-Br$
0%
$p-N$ $\equiv C-$ $C_{6}H_{4}-CH_{2}-Br$
0%
$C_{6}H_{5}-CH_{2}-Br$

Which of the following compounds are optically active ?

0%
$CH_3-CHOH-CH_2-CH_3$
0%
$H_2C = CH-CH_2-CH=CH_2$
0%
0%

Arrange the following in order of decreasing rate in an

$E_2$ reaction

0%
$1 > 2 > 3$
0%
$3 > 1 > 2$
0%
$3 > 2 > 1$
0%
$2 < 3 < 1$

The major product of the following reaction is:

Which of the these compounds represents the major monobromination isomer formed in the following reaction?

Product (D) in the reaction is:

0%
optically active cyanide
0%
optically inactive acid
0%
optically active acid
0%
optically active aldehyde

Explanation

In the following reaction first step is Wurtz reaction and then Bromine addition which further react with

$KCN$ and after hydrolysis it gives the optically inactive carboxylic acid.

Option B is correct.

1095169_1184045_ans_1ea35cd270a2455881e68fef8e4ccce0.png

The reagent used in dehydrohalogenation process is

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alcoholic KOH
0%
$NaNH_2$
0%
$C_2H_5ONa$
0%
All of these

Which one of the following compound is most reactive towards

$SN^1$ reaction

Explanation

The compound which forms most stable carbocation is most reactive towards

$SN^1$ reaction.

Here, is most reactive towards

$SN^1$ reaction.

(

$\because Br$ is better leaving group compared to Cl)

1045015_1178216_ans_920b420f7bd44d97b424267a65573a6e.png

The IUPAC name of this compound is-

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2- Flouro-4-chloro-2,4-diethyl-1-pentane
0%
3-Flouro-5-chloro-3-methyl-5-ethyl-1-hexane
0%
3-Chloro-5-fluoro-3,5-dimethyl-1-heptane
0%
3,5-Dimethyl-5-fluoro-3-chloro-heptane

2-methylbut -3-en-2-ol reacts with

$HBr$ and

0%
Produces $1^\circ$ - Bromide as major product through $S_N 1$ mechanism
0%
Produces $3^\circ$ - Bromide as major product through $S_N 1$ mechanism
0%
Produces $1^\circ$ - Bromide as major product through $S_N 2$ mechanism
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Produces $3^\circ$ - Bromide as major product through $S_N 2$ mechanism

Mark the true statement concerning mesomeric effect?
a) It occurs in system having conjugate double bonds in compounds
b) It involves electrons of

$\pi$ bonds
c) The electron pair is transferred completely
d) It involeves lone pair of elctrons

0%
True
0%
False

Explanation

All the statement concerning mesomeric effect are true, other name is Resonance effect. It is of two types

$+ M$ or

$+ R$ ,

$- M$ or

$- R$

Identify 'Z' in the following reaction series ,

$CH_{3}CH_{2}CH_{2}Br \xrightarrow {NaOH} (X) \xrightarrow [ \triangle] {Al_{2}O_{3}} (Y) \xrightarrow {HOCl} (Z)$

Select the incorrect statement (s)

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${{\text{S}}_{\text{N}}}{\text{1}}$ reactions also take place with some elimination.
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${{\text{S}}_{\text{N}}}{\text{2}}$ reactions with chiral compounds gives racemic mixture.
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${{\text{S}}_{\text{N}}}{\text{1}}$ reactions is faster in more polar aprotic solvents.
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All of the above are incorrect statements.

The herbicide 2,4-dichlorophenoxyacetic acid, generally called 2,4-D, is synthesized from 2,4-dichlorophenol and chloroacetic acid. The synthesis involves which of these reactions:

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$\rm{S_N1}$
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$\rm{ArS_N}$
0%
$\rm{S_N2}$
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$\rm{S_Ni}$

Which alcohol will give only

$E_{1}$ reaction?

Identify the following species in which elimination of

$HBr$ of two

$Br$ atoms is stereoselective.

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$CH_{3}CH_{2}CHBr_{2}$
0%
$CH_{3}CH_{2}CH_{2}Br$
0%
$CH_{3}CH_{2}\underset{Br}{\underset{|}{CH}}CH_{2}$
0%
$CH_{3}\underset{Br}{\underset{|}{CH}}\underset{Br}{\underset{|}{CH}}CH_{3}$

Given the correct order of initial

$T$ or

$F$ for the following statements. Use

$T$ if the statement is true and use

$F$ if the statement is false.
I.

$Me-CH=C=C=CH-Br$ is optically active.
II. All optically active compounds are chiral.
III. All chiral pyramidal molecules are optically inactive.
IV.

$CH_{3}-CH_{2}-CH_{2}-COOH$ and

$CH_{3}-CH_2-CH_{3}$ are positional isomers.

0%
$TTTF$
0%
$FTFT$
0%
$FTFF$
0%
$TFTT$

Which of the following compound may be optical active ?

0%
$Co{(en)_2}C{I_2}$
0%
${\left[ {Rh{\rm{ CI Br N}}{{\rm{H}}_3}{\rm{ P}}{{\rm{H}}_3}} \right]^ - }$
0%
$Cu{(en)_2}C{I_2}$
0%
All of these

Explanation

Optical activity requires chirality

${\left[ {RhCIBrN{H_3}P{H_3}} \right]^ - }$

Which of the following compound will rotate the plane polarized light at room temperature?

Alkyl halides can be obtained by all methods except?

0%
$CH_{3}-CH_{2}-CH_{3} + Cl_2 \xrightarrow [ UV\ light ]{ }$
0%
$CH_{3}CH_{2}OH+HCl/ZnCl_{2}\rightarrow$
0%
$C_{2}H_{5}OH+NaCl\rightarrow$
0%
$CH_{3}COOAg+Br_{2}/CCl_{4}\rightarrow$

Compound

$C_4H_8Cl_2 \,(A)$ on hydrolysis gives a compound

$C_4H_8O(B)$ which reacts with hydroxylamine and does not give any test with Tollens regent . What are (A) and (B)?

0%
$1,1-$ Dichlorobutane and butanal
0%
$2,2-$ Dichlorobutane and butanal
0%
$1,1-$ Dicholorobutane and butan $-2-$ one
0%
$2,2-$ Dichlorobutane and butan $-2-$ one

$Compound (refer\ image)\overset { alc. }{ \underset { KOH }{ \longrightarrow } } (A)\overset { NBS }{ \longrightarrow } (B)\overset { alc. }{ \underset { KOH }{ \longrightarrow } } (C)\overset { NBS }{ \longrightarrow } (D)\overset { alc. }{ \underset { KOH }{ \longrightarrow } } (E)$ The product E is

Provide the structure of the major organic product which results in the following reaction.

Which one is not prepared by Wurtz reaction?

0%
$C_4H_8$
0%
0%
$CH_4$
0%

The major product of the following reaction is :

Explanation

When an alkyl bromide is treated with

$\ C_2H_5ONa/ C_2H_5-OH$ , it undergoes dehydrobromintion. A molecule of

$\displaystyle HBr$ is eliminated and

$\displaystyle C=C$ double bond is formed. In present example,

$C=C$ double bond is conjugated with aromatic ring. This leads to stability.

Choose the correct options (s) that gives (s) aromatic compound as the major product:

The compound

$C_{7}H_{8}$ undergoes the following reactions:

$C_{7}H_{8}\xrightarrow {3Cl_{2}/\triangle}A \xrightarrow {Br_{2}/ Fe} B \xrightarrow {Zn/HCl}C$ . The product

$C$ is:

0%
$3-$ bromo $-2,4,6-$ trichlorotoluene
0%
$m-$ bromotoluene
0%
$p-$ bromotoluene
0%
$o-$ bromotoluene

Among the following, the reaction that proceeds through an electrophilic substitution is:

In an

$S_N1$ reaction on chiral centres, there is:

0%
$100$ % retention
0%
$100$ % inversion
0%
$100$ % racemization
0%
Inversion more than retention leading to initial racemization

Explanation

In an

$S_N1$ reaction on chiral centres, there is inversion more than retention leading to initial racemization.

Thus if we start with a pure enantiomer and carry out

$S_N1$ substitution on chiral carbon, the product will be racemic. This is because a planar carbocation intermediate is obtained. The nucleophile can attack from either side of this intermediate.

Option D is correct.

Which of the following is the most correct electron displacement for a nucleophilic reaction to take place?

Which of the following alkane cannot be made in good yield by Wurtz reaction?

0%
2,3-Dimethylbutane
0%
n-Heptane
0%
n-Butane
0%
n-Hexane

CBSE Questions for Class 12 Engineering Chemistry Haloalkanes And Haloarenes Quiz 2 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry Haloalkanes And Haloarenes Quiz 2 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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