Chapter 4, Problem 18A

(a)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion nitrate is to be written.

Concept introduction:

Oxyanion is a class of polyatomic ions. Polyatomic ion involves more than one atom which carries a net charge and exists as a single unit. Oxyanion is an anion of oxygen and another non-metal. For example: sulphate ion $(S{O}_4{}^{2-})$ , Phosphate ion $(P{O}_4{}^{3-})$

Answer to Problem 18A

  $N{O}_3{}^{-}$

Explanation of Solution

Nitrate ion is the standard oxyanion of nitrogen. It is a polyatomic ion in which one atom of nitrogen is bonded with three oxygen atom with one unit negative charge. Its formula is $N{O}_3{}^{-}$.

(b)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion nitrite is to be written.

Concept introduction:

Oxyanion is a class of polyatomic ions. Polyatomic ion involves more than one atom which carries a net charge and exists as a single unit. Oxyanion is an anion of oxygen and another non-metal. For example: sulphate ion $(S{O}_4{}^{2-})$ , Phosphate ion $(P{O}_4{}^{3-})$

Answer to Problem 18A

  $N{O}_2{}^{-}$

Explanation of Solution

Nitrate ion is the standard oxyanion of nitrogen. Its formula is $N{O}_3{}^{-}$. So, nitrite ion involves replacement of ‘ate’ by ‘ite’. So, the formula of nitrite ion is $N{O}_2{}^{-}$.

(c)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion ammonium is to be written.

Concept introduction:

Polyatomic ion involves more than one atom which carries a net charge and exists as a single unit. For example: sulphate ion $(S{O}_4{}^{2-})$ , Phosphate ion $(P{O}_4{}^{3-})$

Answer to Problem 18A

  $N{H}_4{}^{+}$

Explanation of Solution

Ammonium ion is a polyatomic ion of nitrogen and hydrogen. It is formed when ammonia shares its lone pair with hydrogen. So, the formula of ammonium ion is $N{H}_4{}^{+}$.

(c)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion cyanide is to be written.

Concept introduction:

Polyatomic ion involves more than one atom which carries a net charge and exists as a single unit. For example: sulphate ion $(S{O}_4{}^{2-})$ , Phosphate ion $(P{O}_4{}^{3-})$

Answer to Problem 18A

  $C{N}^{-}$

Explanation of Solution

Cyanide ion is composed of carbon and nitrogen with one unit negative charge. So, the formula of cyanide is $C{N}^{-}$.