Russian chemist Vladimir Markovnikov proposed Markovnikov’s rule in 1869 to predict the regiochemistry of addition reactions between unsymmetrical alkenes/ alkynes and hydrogen halides to form alkyl halides.
According to the rule, ‘An alkyl halide is formed in a reaction between an unsymmetrical alkene or alkyne and hydrogen halide (HX) when the negative part of the reagent (X-) attaches to the alkene carbon that has fewer number of hydrogen atoms across the double bond.’
A carbocation is a positively charged, electron-deficient carbon ion that acts as a reactive intermediate in many organic reactions.
The central carbon in a carbocation has only 6 valence electrons instead of the preferred 8 by covalent bonding. As a result, it has only three covalent bonds and, therefore, trivalent.
Learning Objective: To learn about the molecular mass and its calculation from atomic weights.
Skill Level – Intermediate
Prerequisites:
The three common hybridization states are - sp3, sp2, and sp. The sp3 (pronunciation: ess-pee-three) hybridization of Carbon explains its four bonds’ tetravalency, shape, and equivalency.
Learning Objective: To study the nucleophiles that function as sigma bond donors that form Carbon, Hydrogen, and Halogen bonds with the substrate.
Prerequisites:
Electronegativity trend of the elements from the Periodic table
The process of heating a solid metal or glass to a specific high temperature and gradual cooling is called annealing. The physical property (strength, elasticity and crystalline property) of a solid can be altered by this method.
Learning Objective: To learn about the average atomic mass and how to calculate it from its isotopic mass and natural abundance.
Skill Level – Intermediate
Prerequisites:
Collision theory is applicable only to bimolecular reactions mostly gases where the reactant molecules are considered as hard spheres that must collide with sufficient threshold energy and must be correctly oriented for the collision to be effective that results in the product formation.
The rate of the reaction, therefore, depends on the collision frequency, threshold energy, and the orientation (steric/probability) factor.
k= PZABe-Ea/RT
where,
| Addition Reaction | Elimination Reaction | |
|---|---|---|
Process | Two molecules combine in an addition reaction to form a single addition product (adduct).
| Elimination reaction involves loss of two groups and formation of a new bond. |
Mechanism | The addition can take place by heterolytic, homolytic, or pericyclic methods. |
Van der Waals forces are weak intermolecular attractive forces that occur in polar and nonpolar atoms or molecules due to the shift in their electron positions.
The electrons shift to form electron-dense and electron-deficient poles. Some poles are permanent due to the nature of the atom in a molecule, while others are induced poles.