NEET Chemistry The p-Block Elements (XII) Questions Solved


Give reasons for the following:

(i) Where R is an alkyl group, R3P=O exists but R3N=O does not.

(ii) PbCl4 is more covalent than PbCl2.

(iii) At room temperature, N2 is much less reactive.

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#6 | 16th Group

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group 16,preparation and properties

(i) Due to presence of d-orbitals in P, it can form pπ-dπ bonds and can extend its covalency beyond 4 while N cannot do so due to absence of d-orbitals.

(ii) According to Fajan's rule, highly charged Pb4+ can polarise the anion i.e., Cl- more effectively than Pb2+ and hence PbCl4 becomes more covalent than PbCl2.

(iii) Due to presence of triple bonds between 2N atoms, their bond length decreases and hence bond dissociation energy increases which makes N2 lesser reactive. While in phosphorus due to presence of single bond, more bond length, bond dissociation energy is low, hence very reactive.

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