Nucleophilic And Electrophilic Substitution Reactions Both Aromatic And Aliphatic

Let's match each item from List-I with the correct statement from List-II:
(A) Ambient nucleophiles:
Ambient nucleophiles refer to molecules or ions that are nucleophilic (able to donate electrons) in nature. They are often involved in nucleophilic substitution reactions. This corresponds to cyanides and nitriles (III), which are typical examples of nucleophilic compounds.
(B) Plane polarized light:
Plane polarized light refers to light waves oscillating in only one plane. This property is related to optical activity, which can be detected using a Nicol Prism (IV), a device used to produce plane polarized light.
(C) Superimposable mirror image:
A superimposable mirror image occurs when an object can be overlapped onto its mirror image, indicating that the object is symmetrical (I). For example, a symmetrical molecule or object has mirror images that can be perfectly superimposed.
(D) -elimination reaction:
The -elimination reaction is a reaction where elements or groups are removed from adjacent carbon atoms, often leading to the formation of alkenes. The Saytzeff rule (II) is applied in these reactions, predicting the formation of the more substituted product.
Conclusion:
Thus, the correct matching is:
- (A) Ambient nucleophiles → (III) Cyanides and nitriles
- (B) Plane polarized light → (IV) Nicol Prism
- (C) Superimposable mirror image → (I) Symmetrical object
- (D) -elimination reaction → (II) Saytzeff rule
Final Answer:

Step 1: Nucleophilic Addition Reaction.
Nucleophilic addition reactions involve nucleophilic attack on the carbonyl group (C=O) of aldehydes and ketones. The reactivity depends on the steric and electronic factors around the carbonyl group.
Step 2: Analyze the Compounds.
- (A) Ethanal: Ethanal is an aldehyde, and aldehydes are typically more reactive than ketones due to less steric hindrance.
- (B) Propanone: Propanone is a ketone with two methyl groups attached to the carbonyl carbon, making it less reactive than aldehydes.
- (C) Propanal: Propanal is an aldehyde, similar to ethanal but with a propyl group attached, making it slightly less reactive than ethanal.
- (D) Butanone: Butanone is a ketone with larger alkyl groups, thus the least reactive in nucleophilic addition.
Step 3: Conclusion.
The correct sequence of increasing reactivity is:
(1) (A) Ethanal → (2) (B) Propanone → (3) (C) Propanal → (4) (D) Butanone.
Final Answer:

Step 1: Understanding S 2 mechanism.
In the S 2 (bimolecular nucleophilic substitution) mechanism, the nucleophile attacks the electrophilic carbon from the opposite side of the leaving group, resulting in the inversion of configuration. This happens because the nucleophile attacks from the backside, causing a flip in the configuration of the molecule.
Step 2: Evaluate each option.
- Option 1: Retention of configuration: Retention of configuration occurs in the S 1 mechanism, where the intermediate carbocation can undergo either attack from the nucleophile on the same side or opposite side, leading to retention or inversion. It does not occur in the S 2 mechanism.
- Option 2: Racemic mixture: A racemic mixture is typically formed in the S 1 mechanism due to the possibility of nucleophilic attack from either side of the planar carbocation. However, in S 2, only inversion of configuration occurs, not a racemic mixture.
- Option 3: Inversion of configuration: This is the correct answer. In the S 2 mechanism, the nucleophile attacks the carbon from the opposite side of the leaving group, causing an inversion of the configuration.
- Option 4: Formation of carbocation: Carbocation formation is a key feature of the S 1 mechanism, not the S 2 mechanism. In S 2, there is no formation of a carbocation.
Step 3: Conclusion.
The optically active alkyl halide undergoing S 2 substitution involves inversion of configuration.
Final Answer: