Chapter 4, Problem 7STP

Interpretation Introduction

Interpretation: Correct formula of the Oxyacids needs to be determined.

Concept introduction: Oxyacids compounds that contain hydrogen, oxygen, and at least one other element. They are bonded such that, they show acidic characters.

The rules which are used to name series of oxyanions are:

• The standard anion ends with ‘ate’.
• For the anion carrying one more oxygen, prefix ‘per’ is used.
• The anion carrying one less oxygen atom ends with ‘ite’.
• The anion carrying two less oxygen ends with ‘ite’ and prefix ‘hypo’ is also used.
• For oxyacid, in last acid is added.

Answer to Problem 7STP

(B)

Explanation of Solution

In case of acid, nomenclature is derived from anion’s name which they usually form when dissolute in ${\text{H}}_2\text{O}$ .For polyatomic anion with two oxygen the acid will have the suffix “-ous.” So, in case of ${\text{ClO}}^{-}$ chlorous is used.

Correct formula of the chlorous acid is ${\text{HClO}}_2$ .

Conclusion

Those acids which have oxygen atom one extra than those present in “-ate” ion, then “per-” as prefix and “-ic”as suffix is used.Such as ${\text{ClO}}_4{}^{-}$ ion is termed asperchlorate ion.Therefore, HClO₄ is called perchloric acid.

Similarly, ${\text{HClO}}_3$ is named as chloric acid.With two fewer oxygen than the “-ate” ion, the prefix will be “hypo-” and the suffix will be “-ous.” For example, instead of chloric acid we have hypochlorous acid, HClO.