Basing on the nature of the attacking site in the substrate, attacking reagents are classified as nucleophiles and electrophiles

When the transfer of electrons takes place towards the attacking reagent, it is +E effect. Eg. Addition of acids to alkenes

The products of bond breaking, shown below, are not stable, and cannot be isolated for prolonged study. Such species are referred to as reactive intermediate, and are belived to be transient intermediates in many reactions. The general structures and names of four such intermediates are, Charged Intermediates Uncharged Intermediates Carbocations (called carbonium ions in the older literature) are electrophiles and carbananions are nucleophiles. Carbenes have only a valence shell sextet of electrons and are therefore electron deficient. In this sense they are elecrophiles, but the non-bonding electron pair also gives carbenes nucleophilic character. As a rule, the electrophilic character dominates carbene reactivity. Carbon radicals have only seven valence electrons, and may be considered electron deficient, however, they do not in general bond to nucleophilic electron pair, so their chemistry exhibits differences from that of conventional electrophiles. Radical intermediates are often called free radicals. Intermediates are in general stabilised with conjugation, electron donating and electron with drawing groups. R-N^(+) equiv N" "Cl^(-) rarr R^(+)+N_(2)+Cl^(-) based on the above, which of the following from R^(+) most readily

The products of bond breaking, shown below, are not stable, and cannot be isolated for prolonged study. Such species are referred to as reactive intermediate, and are belived to be transient intermediates in many reactions. The general structures and names of four such intermediates are, Charged Intermediates Uncharged Intermediates Carbocations (called carbonium ions in the older literature) are electrophiles and carbananions are nucleophiles. Carbenes have only a valence shell sextet of electrons and are therefore electron deficient. In this sense they are elecrophiles, but the non-bonding electron pair also gives carbenes nucleophilic character. As a rule, the electrophilic character dominates carbene reactivity. Carbon radicals have only seven valence electrons, and may be considered electron deficient, however, they do not in general bond to nucleophilic electron pair, so their chemistry exhibits differences from that of conventional electrophiles. Radical intermediates are often called free radicals. Intermediates are in general stabilised with conjugation, electron donating and electron with drawing groups. R-N^(+) equiv N" "Cl^(-) rarr R^(+)+N_(2)+Cl^(-) based on the above, which of the following from R^(+) most readily

SN^1 reaction is given by alkylhalide which forms stable carbocation during reaction. The carbonation, has sp^2 hybridisation. In SN^1 reaction, the attack of the nucleophile to carbocation inter mediate is from either side. In SN^2 reaction the attacking nucleophile attacks from the back leading to the formation of inversion complex. Alcohol reacts with PCI_5 to give alkyl chloride by an internal attack of nucleophile with in the molecule. In the following reaction

SN^1 reaction is given by alkylhalide which forms stable carbocation during reaction. The carbonation, has sp^2 hybridisation. In SN^1 reaction, the attack of the nucleophile to carbocation inter mediate is from either side. In SN^2 reaction the attacking nucleophile attacks from the back leading to the formation of inversion complex. Alcohol reacts with PCI_5 to give alkyl chloride by an internal attack of nucleophile with in the molecule. In the following reaction

(A) Enzymes have active sites that hold substrate molecule for a chemical reaction. (R) Drugs compete with natural substrate by attaching to the active site of enzyme are called antagonists.

Nucleophiles act as Lewis bases and electrophiles act as Lewis acids

SN^1 reaction is given by alkylhalide which forms stable carbocation during reaction. The carbonation, has sp^2 hybridisation. In SN^1 reaction, the attack of the nucleophile to carbocation inter mediate is from either side. In SN^2 reaction the attacking nucleophile attacks from the back leading to the formation of inversion complex. Alcohol reacts with PCI_5 to give alkyl chloride by an internal attack of nucleophile with in the molecule. In the following reaction . If R is H - undersetoverset(|)(D)oversetunderset(|)(CH_3)(C ) - R - OH underset(Py)overset(SOCl_2)(to) R - Cl + SO_2 + HCl

Classify the following solids in different categories based on the nature of intermolecular forces operating in them : Potassium sulphate , tin , benzene , urea , ammonia , water , zinc sulphide , graphite , rubidium , argon , silicon carbide .

Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles: (a) CH_(3)COOH+HO^(-)rarrCH_(3)COO^(-)+H_(2)O (b) CH_(3)COCH_(3)+overset(-)(C )Nrarr(CH_(3))_(2)C(CN)(OH) (c ) C_(6)H_(5)+CH_(3)overset(+)(C )OrarrC_(6)H_(5)COCH_(3)