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Arrange HCIO_4, HCIO_3, HCIO_2 and HCIO in the increasing order of acidic strength and explain on the basis of the structure of their anions. |
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Answer» SOLUTION :The increasing order of acid STRENGTH is : `HCIO ltHCIO_2ltHCIO_3ltHCIO_4` Reason. This can be explained on the basis of Lowry Bronsted concept. According to this concept, a strong acid has a weak conjugate base and a weak acid has a strong conjugate base. Let us consider the stabilities of the conjugate bases, `ClO^(-), ClO_2^(-) , ClO_3^(-) ` and `ClO_4^(-)`formed from these acids, `HCIO, HCIO_2, HCO_3 ` and `HCIO_4`respectively. These anions are stabilized by the delocalisation of the CHARGE between oxy gen atoms. If the ion is stabilized to greater extent, it has lesser attraction for the proton and therefore, will behave as weaker base (lesser tendency for the reaction to go in backward direction). Consequently, the corresponding acid will be strong because weak conjugate base has strong acid and strong conjugate base has weak acid and vice VERSA. Now, the charge stabilization is minimum in `ClO^-`and maximum in `ClO_4^-`. The charge stabilization increases in the order: `HClO^(-) LT HClO_(2)^(-) lt HClO_(3)^(-) lt HClO_(4)^(-)`  This means that `CIO^-`will have minimum stability and therefore, will have maximum attraction for the `H^+` . In other words, `ClO^-`will be strongest base and so its conjugate acid HCIO will be the weakest acid.Similarly, in this series, `ClO_(4)^(-)`is the weakest base (maximum stabilized) and its conjugate acid `HCIO_4`is the strongest acid. Thus, the acidic strength increases in the order. `HClO lt HClO_2 lt HClO_3 lt HClO_4` |
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