Posts

Showing posts with the label Bimolecular Nucleophilic substitution(SN2) Reactions

Depression in Freezing point and Elevation in Boiling point

-
Image
Depression in Freezing Point: Depression in freezing point means freezing point of solution is always less than that of its pure solvent due to lowering of vapour pressure of solution. Depression in freezing point have the formula as given below, ∆T f = i × K f × m                                       eq.. (1) K f = cryoscopic constant This equation tells us that depression of freezing point depends only on   molality of solutions, so it is a colligative property. m= 1000W 2 /W 1 ×M 2                           putting the value of molality in we get          ∆T f   = i × K f × 1000W 2 /W 1 ×M 2        ...
Post a Comment
Read more

Bimolecular Nucleophilic substitution(SN2) Reactions

-
Image
  What are Bimolecular Nucleophilic substitution(S N 2) Reactions? Discuss factors affecting the rate of these reactions.   Bimolecular Nucleophilic substitution(S N 2) Reactions: The abbreviation S N 2 conveys the information, substitution-nucleophilic-bimolecular. In S N 2 reactions only one step is involved without the formation of intermediate. Nucleophile attacks the substrate from the side opposite to the leaving group, i.e. from the backside. This results in an inversion process for the other groups on carbon center under attack, rather like an umbrella turning inside out in a violent gust of wind. The bond formation between the nucleophile and substrate and the bond cleavage resulting in the removal of leaving group occur simultaneously, i.e. the reaction is concerted one . As the nucleophile starts making bond with the central carbon atom of the substrate, the leaving group starts leaving it and in the transition state both the nucleophile and the leavin...
Post a Comment
Read more

Popular posts from this blog

Balancing Redox Reactions by Ion-Electron method(part1)

-
Image
  How to balance redox reactions? How can we balance redox reactions by Ion-Electron method? Balancing redox reactions: The balancing of redox equations by the loss and gain of electrons, usually involves quite a few ions, which do not undergo change in valence and which are not necessary for the process of balancing. The ion –electron method eliminates a unnecessary ions and retains only those, which are essential. Following are the general rules for balancing redox equations by ion- electron method. 1.    Assign oxidation states to determine species being oxidized and reduced, and write the half reactions. 2.    Balance each half reaction. a.    Balance the atoms being oxidized or reduced. b.    Balance oxidation number by adding electrons. c.    Balance the other elements that are present, for example S with SO 4 2- or Cl with Cl 1- . d.    Balance oxygen atoms by adding H 2 O. e.    Balan...
Read more

Paramagnetic, Diamagnetic, Ferromagnetic, Antiferromagnetic and Ferrimagnetic behavior of substances

-
Image
What is Paramagnetic, Diamagnetic, Ferromagnetic, Antiferromagnetic and Ferrimagnetic behavior of substances? What is the effect of temperature on these properties? Paramagnetic substances: These substances are attracted by the magnetic field and have unpaired electrons. These lose magnetism in the absence of magnetic field. Some examples of paramagnetic substances are transition metals like Cr, Mn, Co, Fe and metal oxides like CuO,VO 2 . Diamagnetic substances: These substances are weakly repelled by magnetic field and have no unpaired electrons. Some examples of diamagnetic substances are H 2 O, benzene, NaCl, TiO 2 . Ferromagnetic substances: Such substances are strongly attracted by magnetic field. In the absence of magnetic field magnetic field these substances have magnetic domains randomly oriented in such a way that their overall magnetic moment gets cancelled. But in the presence of magnetic field they are oriented in such a way that they together produce a str...
Read more

Slater's Rule

-
Image
         What is Slater's Rule and its significance? How to calculate value of σ  and Zeff using Slater' Rule: Slater's Rule : Slater’s rules are a set of empirical guidelines used to calculate the shielding constant (σ) and the effective nuclear charge (Zeff) experienced by an electron in a multi-electron atom. They were introduced by John C. Slater to simplify the complex quantum mechanical interactions between electrons. These rules estimate how much the inner electrons reduce the attractive force of the nucleus on outer electrons. Mathematically:                              Zeff=Z−S where: Z = atomic number (total nuclear charge)             S = shielding constant (calculated using Slater’s rules Significance of Slater's Rule: To quanti...
Read more