Chapter 9, Problem 1STP

Interpretation Introduction

Interpretation: The pair in which the formula of the ion does not match the name has to be identified.

Concept Introduction: Polyatomic ions are ions that have more than one atom. While naming polyatomic ions, the name of the less electronegative element is placed first, followed by the higher electronegative element. ‘−ate’ or ‘-ite’ is used as a suffix for anions.

Answer to Problem 1STP

The pair in which the name does not match the given formula is nitrite, ${\text{NO}}_{\text{3}}{}^{-}$ . Hence option B is the correct answer.

Explanation of Solution

The nitrite ion is composed of one nitrogen and two oxygen along with -1 charge. The chemical formula of nitrite ion is ${\text{NO}}_{\text{2}}{}^{-}$ . Thus, option (B) is correct.

Conclusion

A sulfite ion is a divalent anion containing one sulfur atom and three oxygen atoms with the formula ${\text{SO}}_{\text{3}}{}^{\text{2-}}$ . Hydroxide ion is chemically represented as ${\text{OH}}^{-}$ . Similarly, dichromate is ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}{}^{2-}$ .

Thus, the option (A), (C), and (D) are incorrect.