Question

Why are pentahalides more covalent than trihalides ?

Accepted Answer

The oxidation state of $+ 5$ in pentahalides is more covalent as compared to the $+ 3$ oxidation state in trihalides. Due to the higher positive oxidation state of the central atom in pentahalide state, these atoms will have larger polarising power than the halogen atom attached to them since the polarising power is directly proportional to the charge.

The central atom in pentahalide state will tend to polarise more the halide ion to which it is attached. In the case of trihalides, the central atom will polarise the halogen atom to a lesser extent as compared to a pentahalide state. More is the polarisation, larger will be the covalent character of the bond. Hence, due to larger polarisation of bond in pentahalide state as compared to trihalide state, the pentahalides are more covalent than trihalides.

Andhra Pradesh Board Solutions for Chapter: p-Block Elements, Exercise 1: Intext Questions

Andhra Pradesh Board Chemistry Solutions for Exercise - Andhra Pradesh Board Solutions for Chapter: p-Block Elements, Exercise 1: Intext Questions

Questions from Andhra Pradesh Board Solutions for Chapter: p-Block Elements, Exercise 1: Intext Questions with Hints & Solutions

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