Chapter 13, Problem 13.79QP

Indicate which compound in each of the following pairs is more likely to form ion pairs in water: (a) NaCl or Na₂SO₄, (b) MgCl₂ or MgSO₄ (c) LiBr or KBr.

Interpretation Introduction

Interpretation:

In the given pairs of compound, which are more likely to form ion pairs in water has to be indicated.

Concept introduction:

A couple of oppositely charged ions are connected together by Coulomb attraction without formation of covalent bond known as ‘ion pair’.

Coulomb’s law: This law states that oppositely charges are attracts each other with a force proportional to the product of the charges and inversely proportional to the distance between the charges and likely charges repels each other.

$\text{F}\propto \frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

$\text{F=k}\frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

Where,

${\text{q}}_{\text{1}}{\text{and q}}_{\text{2}}\text{- signed magnitude of charges}$

${\text{d}}^{\text{2}}\text{-Distance between the charge}$

K - Coulomb’s law constant

Answer to Problem 13.79QP

The pairs that forms ion pairs in water is $\text{NaCl}$

Explanation of Solution

To explain ion pair of $\text{NaCl}$ is more likely in water than ${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$

Sodium chloride is an ionic substance which is placed in water, molecules of water interact with the ions on the surface of Sodium and chloride ion. If $\text{NaCl}$ is soluble, interaction with water molecule is more than the attraction within the lattice.  Separated ions moves in the solution and anions with the hydrogen going towards the negative- charged ion.  Other hand positively charged ion moves towards the lone pairs of electrons on Oxygen. Other hand,

Coulombs equation for ${\text{NaCl and Na}}_{\text{2}}{\text{SO}}_{\text{4}}$

$\text{F=k}\frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

Distance between Sodium and chloride ion is 0.281nm which is smaller than the distance between Sodium and sulphate ion. According to Coulombs law, distance between the ions is smaller means the force of attraction is high. Hence the attraction of Sodium chloride and water is larger. So it forms ion pair mostly than Sodium sulphate.

Interpretation Introduction

Interpretation:

In the given pairs of compound, which are more likely to form ion pairs in water has to be indicated.

Concept introduction:

A couple of oppositely charged ions are connected together by Coulomb attraction without formation of covalent bond known as ‘ion pair’.

Coulomb’s law: This law states that oppositely charges are attracts each other with a force proportional to the product of the charges and inversely proportional to the distance between the charges and likely charges repels each other.

$\text{F}\propto \frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

$\text{F=k}\frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

Where,

${\text{q}}_{\text{1}}{\text{and q}}_{\text{2}}\text{- signed magnitude of charges}$

${\text{d}}^{\text{2}}\text{-Distance between the charge}$

K - Coulomb’s law constant

Answer to Problem 13.79QP

The pairs that forms ion pairs in water is ${\text{MgCl}}_{\text{2}}$

Explanation of Solution

To explain ion pair of ${\text{MgCl}}_{\text{2}}$ more likely in water than ${\text{MgSO}}_{\text{4}}$

Magnesium chloride soluble in water while placed in water; molecules of water interact with the ions on the surface of Magnesium and chloride ion.  If ${\text{MgCl}}_{\text{2}}$ is soluble, interaction with water molecule is more than the attraction within the lattice.  Separated ions moves in the solution and anions with the hydrogen going towards the negative- charged ion.  Other hand positively charged ion moves towards the lone pairs of electrons on Oxygen. Other hand,

Coulombs equation for ${\text{MgCl}}_{\text{2}}{\text{ and MgSO}}_{\text{4}}$

$\text{F=k}\frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

Distance between Magnesium and chloride ion is 0.281nm which is smaller than the distance between Magnesium and sulphate ion. According to Coulombs law, distance is smaller means the force of attraction is high. Hence the attraction of Sodium chloride and water is larger. So it forms ion pair mostly than Magnesium sulphate.

Interpretation Introduction

Interpretation:

In the given pairs of compound, which are more likely to form ion pairs in water has to be indicated.

Concept introduction:

A couple of oppositely charged ions are connected together by Coulomb attraction without formation of covalent bond known as ‘ion pair’.

Coulomb’s law: This law states that oppositely charges are attracts each other with a force proportional to the product of the charges and inversely proportional to the distance between the charges and likely charges repels each other.

$\text{F}\propto \frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

$\text{F=k}\frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

Where,

${\text{q}}_{\text{1}}{\text{and q}}_{\text{2}}\text{- signed magnitude of charges}$

${\text{d}}^{\text{2}}\text{-Distance between the charge}$

K - Coulomb’s law constant

Answer to Problem 13.79QP

The pairs that forms ion pairs in water is $\text{KBr}$

Explanation of Solution

To explain ion pair of $\text{KBr}$ more likely in water than $\text{LiBr}$

Potassium bromide is water soluble, when the molecules of water interact with the ions on the surface of Potassium and bromide ion. If $\text{KBr}$ is soluble, interaction with water molecule is more than the attraction within the lattice.  Separated ions moves in the solution and anions with the hydrogen going towards the negative- charged ion.  Other hand positively charged ion moves towards the lone pairs of electrons on Oxygen. Other hand,

Coulombs equation for $\text{LiBr and KBr}$

$\text{F=k}\frac{{\text{q}}_{\text{1}}{\text{q}}_{\text{2}}}{{\text{d}}^{\text{2}}}$

Distance between Magnesium and chloride ion is 0.281nm which is smaller than the distance between Magnesium and sulphate ion.  According to Coulombs law, distance is smaller means the force of attraction is high.  Hence the attraction of Sodium chloride and water is larger.  So it forms ion pair mostly than Magnesium sulphate.

Conclusion

The compounds that are more likely to form ion pairs in water have been indicated.