The p-Block Elements

The p-Block Elements

Question

Among the following oxoacids, the correct decreasing order of acid strength is

  • HOCl > HClO2>HClO3 > HClO4

  • HClO4>HOCl> HClO2>HClO3

  • HClO4>HClO3>HClO2>HOCl

  • HClO2>HClO4>HClO3>HOCl

Answer

C.

HClO4>HClO3>HClO2>HOCl

Decreasing order of strength of oxoacids
HClO4> HClO3>HClO2>HOCl
Reason: consider the structure of conjugate bases of each oxyacid of chlorine.

A negative charge is more delocalised on ClO4- due to resonance, hence ClO4- is more stable (and less basic).
Hence, we can say as the number of the oxygen atom (s) around C|-atom increases as oxidation number of Cl- atom increases and thus, the ability of loose the H+ increases.

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