Chemistry  >  Chemistry for GRE Paper II  >  Test: Reaction Mechanism Level - 1 Download as PDF

Test: Reaction Mechanism Level - 1


Test Description

30 Questions MCQ Test Chemistry for GRE Paper II | Test: Reaction Mechanism Level - 1

Test: Reaction Mechanism Level - 1 for Chemistry 2022 is part of Chemistry for GRE Paper II preparation. The Test: Reaction Mechanism Level - 1 questions and answers have been prepared according to the Chemistry exam syllabus.The Test: Reaction Mechanism Level - 1 MCQs are made for Chemistry 2022 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Test: Reaction Mechanism Level - 1 below.
Solutions of Test: Reaction Mechanism Level - 1 questions in English are available as part of our Chemistry for GRE Paper II for Chemistry & Test: Reaction Mechanism Level - 1 solutions in Hindi for Chemistry for GRE Paper II course. Download more important topics, notes, lectures and mock test series for Chemistry Exam by signing up for free. Attempt Test: Reaction Mechanism Level - 1 | 30 questions in 90 minutes | Mock test for Chemistry preparation | Free important questions MCQ to study Chemistry for GRE Paper II for Chemistry Exam | Download free PDF with solutions
1 Crore+ students have signed up on EduRev. Have you?
Test: Reaction Mechanism Level - 1 - Question 1

Which of the following statements regarding the E2 mechanism is wrong?

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 1

E2 stands for bimolecular elimination. The reaction involves a one-step mechanism in which carbon-hydrogen and carbon-halogen bonds break to form a double bond (C=C Pi bond).

Test: Reaction Mechanism Level - 1 - Question 2

The major product P formed in the given reaction is:

Test: Reaction Mechanism Level - 1 - Question 3

The above reaction is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 3

It is nucleophilic substitution reaction which is in first order.

Test: Reaction Mechanism Level - 1 - Question 4

The major product formed in the following reaction is:

Test: Reaction Mechanism Level - 1 - Question 5

Predict the major product P in the following reaction:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 5

correct ans is 'A'

Test: Reaction Mechanism Level - 1 - Question 6

The major product formed in the following reaction is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 6

Test: Reaction Mechanism Level - 1 - Question 7

The major product obtained on treatment of the following compound with H2SO4 at 80°C is:

Test: Reaction Mechanism Level - 1 - Question 8

In the following compound, the hydroxy group that is most readily Methylated with C2H2N2 is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 8

The conjugate base obtained by the elimination of protons of q -OH group is stabilized by extended conjugation through carbonyl group. And any of the conjugate base is not stabilized by such a factor so the conjugate base corresponds to q -OH group has stability ,so the H corresponding to this OH group is highly acidic. Consequently the H is captured readily by C2H2N2 and readily gets methylated.

Test: Reaction Mechanism Level - 1 - Question 9

In the reaction, the major product X is:

Test: Reaction Mechanism Level - 1 - Question 10

In the reaction, the major product X is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 10

Aldehyde is more reactive than ketone, so, E alkene is generated on aldehyde.

Test: Reaction Mechanism Level - 1 - Question 11

The major product formed in the following reaction is :

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 11

Hydrolysis of ether. Lone pair of oxygen captures H atom from HI group that is present on the up gives rise to a stable carbocation(Resonance stabilized as well as well +i effect of 1 methyl group) and the reaction proceeds via SN1 pathway where I- acts as a nucleophile, but for other group, formed carbocation is highly unstable and ends up at alcohol.

Test: Reaction Mechanism Level - 1 - Question 12

The major product formed in the following reaction is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 12

It is an example of semipinacol rearrangement. NH2 and OH group will remain in the diequatorial position in cyclohexane chair form. So after treatment with HNO2, NH2 becomes N2+. Then rearrangement takes place through C-C bond migration which is antiperiplanar to N2+. Thus ring contraction takes place and product will be B.

Test: Reaction Mechanism Level - 1 - Question 13

In the cyclisation reaction given below, the most probable product formed is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 13

Test: Reaction Mechanism Level - 1 - Question 14

The major product formed in the following reaction is:

Test: Reaction Mechanism Level - 1 - Question 15

The body of car is repaired with help of a filler which is hardened by addition of:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 15

Benzoyl peroxide induces chain growth polymerization.

Test: Reaction Mechanism Level - 1 - Question 16

The correct order of reactivity of p-halonitrobenzens in the following reaction is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 16
  • This is a classical example of aromatic nucleophilic substitution. Here the reaction proceeds through two steps, in the first step the nucleophile attacks and in the second step the leaving group detaches from the ring.
  • The first step is slow, that is rate determining step because when the nucleophile attacks, the ring loses it's aromaticity and a negative charge arises which take part in resonance with NO2 group.
  • So the departure of the leaving group is not the rate determining step (RDS) so it doesn't matter how the leaving group is, it depends on how much the leaving group stabilises the -ve charge. And it follows the order F > Cl > Br >I
Test: Reaction Mechanism Level - 1 - Question 17

Solvolysis of the optically active compound X gives, mainly:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 17

OTs is a good leaving group. So after departure of the leaving group (OTs-) a carbocation will form whose geometry is planer so there are two possibilities of attacking the nucleophile ( OAc- furnished by AcOK) :

1) above the plane.

2) down the plane.

So a racemic mixture will be formed which is optically inactive. If the nucleophile attacked the carbon centre from down the group then the configuration of the centre will either of the + or - then the racemic mixture was not obtained.

Test: Reaction Mechanism Level - 1 - Question 18

The major product obtained in the following reaction, is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 18

The base will abstract the most acidic Hydrogen and will attack on C2H to give A.

Test: Reaction Mechanism Level - 1 - Question 19

The major product formed in the following reaction is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 19

In the first step of the reaction a quaternary ammonium salt is formed which is then eliminated to form the alkene. The alkene formation proceeds through the E1cB pathway where the acidic beta hydrogen is abstracted by the Base and the carbanion is stabilised by the positively charged leaving group i. e N+(C2H5)CH3 which is a powerful electron withdrawing group and the Hoffman product is predominant product.

Test: Reaction Mechanism Level - 1 - Question 20

Increasing order of stability of following carbocations (give least stable first)?

(I) Tropylium 

(III) (C6H5)2C+
(IV) CH3+

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 20
  • Tropylium - aromatic with 6 pi-electrons (Most stable carbocation)
  • Triphenylmethyl carbocation - Positive charge in resonance with two phenyl rings.
  • Allylic carbonation - Positive charge delocalized over 3 carbons.
  • Methyl carbonation - No stabilizing interactions.
Test: Reaction Mechanism Level - 1 - Question 21

What is the nucleophilicity order for SN2 reaction:

(I) C6H5S
(II) C2H5O
(III) NO3
(IV) CN
(V) I

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 21

PhS- is a better nucleophile in SN2 rxn than any other nucleophile given in the question.

Test: Reaction Mechanism Level - 1 - Question 22

Select order of effectiveness of Lewis acid catalyst in Friedel-Crafts reaction:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 22
  • AlCl3 is the strongest Lewis acid due to the presence of vacant p- and d-orbitals.
  • FeCl3 is a strong Lewis acid by virtue of its empty d-orbitals.
  • BF3 has only p-orbitals that are vacant and is a relatively weak Lewis acid.
  • ZnCl2 has only 1 vacant s-orbital and is the weakest.
Test: Reaction Mechanism Level - 1 - Question 23

For the reaction between alkyl halide and OH- increase in solvent polarity generally:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 23

A polar protic solvent favours SN1 mechanism because polar solvents has the below properties: 

  • It stabilizes the carbocation intermediate. Polar solvents like methanol have a permanent dipole which means that partial negative charge on the molecule will have dipole-dipole interactions with the carbocation, stabilizing it.
  • It reduces the reactivity of the nucleophile. The polar solvent can interact electrostatically with the nucleophile. This reduces the reactivity of the nucleophile and enhances the SN1 reaction.
Test: Reaction Mechanism Level - 1 - Question 24

In an SN2 reaction there is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 24

The SN2 reaction - A Nucleophilic Substitution in which the Rate Determining Step involves 2 components.

SN2 reactions are bimolecular with simultaneous bond-making and bond-breaking steps. -SN2 reactions do not proceed via an intermediate.

In an SN2 reaction there is mostly inversion and little racemisation.

Test: Reaction Mechanism Level - 1 - Question 25

Reactive intermediate formed in the following reaction is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 25

The reaction of bromine with sodium hydroxide forms sodium hypobromite in situ, which transforms the primary amide into an intermediate isocyanate. The formation of an intermediate nitrene is not possible because it also implies the formation of a hydroxamic acid as a byproduct, which has never been observed. The intermediate isocyanate is hydrolyzed to a primary amine, giving off carbon dioxide.

Test: Reaction Mechanism Level - 1 - Question 26

Cannizzaro reaction is not given by:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 26

Cannizzaro reaction is given by aldehydes that do not have a α hydrogen atom. Acetaldehyde (CH3CHO) has 3 α hydrogen atoms and thus does not undergo Cannizzaro reaction.

Test: Reaction Mechanism Level - 1 - Question 27

An SN2 reaction at an asymmetric carbon atom of a dextro alkyl halide always gives a:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 27

In SN2 reaction, inversion of configuration takes place. Since reactant and product are not enantiomers, the sign of the optical rotation may not change, hence a single stereoisomer is obtained.

Test: Reaction Mechanism Level - 1 - Question 28

Reaction of ethyne with HCN in presence of Ba (CN)2 is an example of:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 28

Test: Reaction Mechanism Level - 1 - Question 29

Consider the following carbocations, most stable is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 29
  • The stability of C6H5CH2+ is due to resonance.
  • The stability of C6H5CH2CH2+ is due to only inductive effect.
  • The stability of C6H5CH+CH3 is due to resonance and +I effect of 1 methyl group.
  • The stability of C6H5C+(CH3)2 is due to both resonance and +I effect of 2 methyl groups.

So, the order of stability of carbocation is d>c>a>b or b<a<c<d.

Test: Reaction Mechanism Level - 1 - Question 30

The major product formed in the reaction given below is:

Detailed Solution for Test: Reaction Mechanism Level - 1 - Question 30

132 videos|248 docs|77 tests
Use Code STAYHOME200 and get INR 200 additional OFF
Use Coupon Code
Information about Test: Reaction Mechanism Level - 1 Page
In this test you can find the Exam questions for Test: Reaction Mechanism Level - 1 solved & explained in the simplest way possible. Besides giving Questions and answers for Test: Reaction Mechanism Level - 1, EduRev gives you an ample number of Online tests for practice