Haloalkanes & H...

Passage I

The following E2 is carried out with different halogen substituent:

From the percentage yield of two products observed with different leaving group, it was concluded that both ease of leaving group and steric hindrance to the approach of base CH₃ O^-  to β-H affect the orientation of elimination reaction.

Q. 

During formation of products in the given elimination reaction, the highest energy transition state would have been produced when methoxide ion reacts with

Passage I

The following E2 is carried out with different halogen substituent:

From the percentage yield of two products observed with different leaving group, it was concluded that both ease of leaving group and steric hindrance to the approach of base CH₃ O^-  to β-H affect the orientation of elimination reaction.

Q. 

If we consider X to be iodine in the given elimination reaction, the number of different elimination products present in the flask-1 would be?

Passage I

The following E2 is carried out with different halogen substituent:

From the percentage yield of two products observed with different leaving group, it was concluded that both ease of leaving group and steric hindrance to the approach of base CH₃ O^-  to β-H affect the orientation of elimination reaction.

Q. 

Transition state with maximum double bond character will be formed when methoxide reacts with

Passage I

The following E2 is carried out with different halogen substituent:

From the percentage yield of two products observed with different leaving group, it was concluded that both ease of leaving group and steric hindrance to the approach of base CH₃ O^-  to β-H affect the orientation of elimination reaction.

Q. 

Transition state with least double bond character will be formed when methoxide reacts with

Passage II

When compound 1 is heated with C₂ H₅ ONa compound 2 and 3 are formed:

Two mechanisms were proposed for reaction I.
Mechanism A HBr is eliminated from compound 1 to form a symmetrical vinyl carbene intermediate A, which then rearranges to compound 2.

Mechanism B Ethoxide ion first abstract a proton to form a carbanion intermediate B which then rearranges with loss of bromide ion to form compound 2

To distinguish between the two machanisms, an isotopic labeling experiment was designed. Two compounds (Compound 4 and 5) were labelled with C-14 and each was treated separately with sodium ethoxide under identical experimental condition where following results were obtained.

Q. 

Based on the results of scheme 1, the chemist most likely ruled out mechanism A because they assumed that intermediate A should have formed

Passage II

When compound 1 is heated with C₂ H₅ ONa compound 2 and 3 are formed:

Two mechanisms were proposed for reaction I.
Mechanism A HBr is eliminated from compound 1 to form a symmetrical vinyl carbene intermediate A, which then rearranges to compound 2.

Mechanism B Ethoxide ion first abstract a proton to form a carbanion intermediate B which then rearranges with loss of bromide ion to form compound 2

To distinguish between the two machanisms, an isotopic labeling experiment was designed. Two compounds (Compound 4 and 5) were labelled with C-14 and each was treated separately with sodium ethoxide under identical experimental condition where following results were obtained.

Q. 

Compound 2 and 6 can be distinguished from each other by all of the following techniques except:

Passage II

When compound 1 is heated with C₂ H₅ ONa compound 2 and 3 are formed:

Two mechanisms were proposed for reaction I.
Mechanism A HBr is eliminated from compound 1 to form a symmetrical vinyl carbene intermediate A, which then rearranges to compound 2.

Mechanism B Ethoxide ion first abstract a proton to form a carbanion intermediate B which then rearranges with loss of bromide ion to form compound 2

To distinguish between the two machanisms, an isotopic labeling experiment was designed. Two compounds (Compound 4 and 5) were labelled with C-14 and each was treated separately with sodium ethoxide under identical experimental condition where following results were obtained.

Q. 

In reaction scheme 1, had the α-C to bromine be labelled with C-14

Matching List Type

Direction : Choices for the correct combination of elements from Column I and Column II are given as options (a), (b), (c) and (d), out of which one is correct.

Q. 

Match the reaction from Column I with the type of m echanism from Column II and mark the correct option from the codes given below.

Match the alkyl halides in the Column I with the properties of their products produced in E2 elimination reaction in Column II and mark the correct option from the codes given below.

One Integer Value Correct Type

Direction : This section contains 2 questions. When worked out will result in an integer from 0 to 9 (both inclusive).

Q. 

In the reaction given below how many elim ination products are formed in principle if reaction proceeds by E1 cb mechanism?

Consider the following reaction,

Q. 

How many different stereoisomers of the major elimination product Y are possible?