Chapter 4, Problem 18A

(a)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion phosphide 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

  $P^{3-}$

Explanation of Solution

Phosphide ion is ion of phosphorus carrying three unit negative charge. So, the formula of phosphide ion is $P^{3-}$.

(b)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion phosphate 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

The formula of given polyatomic ion is $P{O}_4{}^{3-}$ .

Explanation of Solution

Phosphate ion is standard oxyanion of phosphorus. It is composed of phosphorus and oxygen atom in 1:4 with three unit negative charge. So, the formula of phosphate ion is $P{O}_4{}^{3-}$.

(c)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion phosphiteis 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

The formula of given polyatomic ion is $P{O}_3{}^{3-}$ .

Explanation of Solution

The formula of phosphate ion is $P{O}_4{}^{3-}$ . In phosphite ion, the suffix ‘ate’ is replaced by ‘ite’. So, it will contain one less oxygen. Therefore, the formula of phophite ion is $P{O}_3{}^{3-}$.

(d)

Interpretation Introduction

Interpretation:

The formula of given polyatomic ion hydrogen phosphate 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

The formula of given polyatomic ion is $HP{O}_4{}^{2-}$ .

Explanation of Solution

The formula of phosphate ion is $P{O}_4{}^{3-}$ . So, the formula of hydrogen phosphate is formed by adding hydrogen ion. So, the formula is $HP{O}_4{}^{2-}$ .