Electrophile: These are electron-deficient species (Lewis acids) that seek electron-rich centers. They can be positively charged ions like H+ or neutral molecules with vacant orbitals like BF3.
Nucleophile: These are electron-rich species (Lewis bases) that donate an electron pair to an electron-deficient center. They can be negatively charged like OH- or neutral molecules with lone pairs like NH3.
Dipole Moment: It is the product of the magnitude of charge (q) and the distance (d) between the centers of positive and negative charges. It is a vector quantity represented as mu = q x d.
Increasing Order: p-dichlorobenzene < m-dichlorobenzene < o-dichlorobenzene. In the para-isomer, the bond dipoles cancel each other out (mu = 0).
Formic acid (HCOOH) is more acidic than acetic acid (CH3COOH). This is because the methyl group in acetic acid has a +I (inductive) effect, which increases electron density on the carboxylate group, destabilizing the conjugate base. Formic acid lacks this destabilizing effect.
Carbanion: A species containing a trivalent carbon atom carrying a negative charge.
Carbon-free radical: A species containing a trivalent carbon atom with one unpaired (odd) electron.
Methyl Carbanion (CH3-): Formed by heterolytic cleavage. The carbon is sp3 hybridized with a pyramidal structure.
Methyl Radical (CH3·): Formed by homolytic cleavage. The carbon is sp2 hybridized with a planar structure.
Triplet Carbene: A species where the two non-bonding electrons occupy different orbitals with parallel spins (sp hybridized)
.Stability: Triplet carbene is more stable because electrons in different orbitals experience less inter-electronic repulsion compared to the paired electrons in a single orbital of a singlet carbene
.In ethylene (C2H4), each carbon is sp2 hybridized. [span_14](start_span)One s and two p orbitals mix to form three sp2 hybrid orbitals (sigma bonds), while one unhybridized p orbital forms a pi bond via lateral overlap[span_14](end_span).
Aliphatic amines are more basic because the lone pair on nitrogen is readily available. In aromatic amines (aniline), the lone pair is delocalized into the benzene ring via resonance, making it less available for donation.
| Inductive Effect | Electromeric Effect |
|---|---|
| Permanent effect. | Temporary effect (requires reagent). |
| Involves sigma electrons. | Involves pi electrons. |
When an unsymmetrical reagent (like HBr) adds to an unsymmetrical alkene, the negative part of the reagent attaches to the carbon atom containing the fewer number of hydrogen atoms
.Example: CH3-CH=CH2 + HBr -> CH3-CH(Br)-CH3
The reaction of alkyl halides with metallic sodium in dry ether to form higher alkanes
.2RX + 2Na -> R-R + 2NaX
A: Propyne ozonide
.B: CH3COCHO (Pyruvaldehyde) + H2O2
.1. Addition of HCl to 3,3-dimethyl-1-butene: Involves a carbocation intermediate and a 1,2-methyl shift to form the more stable tertiary carbocation, resulting in 2-chloro-2,3-dimethylbutane.
2. Dehydrohalogenation: (CH3)3CCl + alc. KOH -> CH2=C(CH3)2 + KCl + H2O (E2 mechanism).
Ozonolysis is the cleavage of an unsaturated bond with ozone to form carbonyl compounds
.Alkene Structure: 2-methyl-2-butene (CH3-C(CH3)=CH-CH3)
.A cyclic, planar, fully conjugated system is aromatic if it contains (4n + 2) pi electrons, where n is a non-negative integer
.Also known as the Kharasch effect, it refers to the anti-Markovnikov addition of HBr to alkenes in the presence of organic peroxides
.1. Acetophenone: Benzene + CH3COCl (Anhyd. AlCl3).
2. BHC: Benzene + 3Cl2 (UV light).
Benzene reacts with an acyl halide in the presence of AlCl3. Mechanism: 1. Formation of acylium ion (R-C+=O). 2. Electrophilic attack on benzene. 3. Loss of proton to restore aromaticity.
Chlorine has a strong -I effect (deactivating), but its lone pairs can be donated via resonance (+R effect), which increases electron density specifically at the ortho and para positions
.Chirality is the geometric property of a molecule being non-superimposable on its mirror image
. In CH3-CHCl-CH(CH3)2, the C2 carbon is chiral.Chair is more stable than Boat. In the chair form, all C-H bonds are staggered, minimizing torsional strain. In the boat form, eclipsed bonds and "flagpole" interactions increase energy.
Epimers: Diastereomers that differ in configuration at only one chiral center (e.g., Glucose and Galactose at C4)
.Anomers: Epimers that differ at the hemiacetal/acetal carbon (C1 in glucose)
.The spontaneous change in the specific rotation of an optically active compound in solution until equilibrium is reached between alpha and beta forms
.