Chapter 6, Problem 42P

Interpretation Introduction

(a)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

The water molecule is formed by the combination of hydrogen and oxygen atoms in 2:1 ratio, the molecular formula of the water is ${\text{H}}_{\text{2}}\text{O}$.

Answer to Problem 42P

True.

Explanation of Solution

Given:

The properties that make water a good solvent are its polarity and its capacity for hydrogen bonding.

The water molecule is polar due to presence of electronegative oxygen and electropositive hydrogen atom, this result in difference in electro-negativities between the atoms in the molecule. This polarity results in good solvent of water as it gives ability to stick to itself, other substances, and have surface tension. The water molecule also forms hydrogen bonding between them due to the presence of oxygen and hydrogen atoms. Due to polarity water forms electrostatic attraction between other polar molecules and ions.

Interpretation Introduction

(b)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

The compounds formed by the complete transfer of electrons between the atoms is said to be the ionic compound and force of attraction between them is electrostatic force of attraction.

Answer to Problem 42P

True.

Explanation of Solution

Given:

When ionic compounds dissolve in water, their ions become solvated by water molecules.

Ionic compounds have atoms which are oppositely charged, known as ions, arranged in such a way to form a lattice. On adding an ionic compound (polar) to water, the ions get attracted to the water molecules as water is also polar in nature. The force of attraction between the ions and water molecule is strong enough to break the bond between the ionic compounds thus, resulting in dissociation of ions and ions gets dispersed in solution by forming the bonds with water (${\text{H}}_{\text{2}}\text{O}$) that is ions are surrounded by water molecules and this process is said to be solvation.

Interpretation Introduction

(c)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

The water molecule is formed by the combination of hydrogen and oxygen atoms in 2:1 ratio, the molecular formula of the water is ${\text{H}}_{\text{2}}\text{O}$.

Answer to Problem 42P

True.

Explanation of Solution

Given:

The term “water of hydration” refers to the number of water molecules that surround an ion in aqueous solution.

Water molecule that is chemically combined with a substance to form a hydrate is said to be the water of hydration. The removal of water hydration can be done (either by heating) that do not change the composition of the substance. The hydration generally occurs with secondary minerals.

For example: ${\text{Al}}_2{\text{O}}_3{\text{.3H}}_{\text{2}}\text{O}$ (hydrated aluminum oxide).

Interpretation Introduction

(d)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

The water molecule is formed by the combination of hydrogen and oxygen atoms in 2:1 ratio, the molecular formula of the water is ${\text{H}}_{\text{2}}\text{O}$.

Answer to Problem 42P

True.

Explanation of Solution

Given:

The term “anhydrous” means “without water”.

The absence of water in a compound is described by the term anhydrous, which means that the structure of compound have no water molecule in it.

Interpretation Introduction

(e)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

On dissolving electrolyte (polar in nature) in polar solvents, they get separated into its respective ions that are cations and anions.

Answer to Problem 42P

True.

Explanation of Solution

Given:

An electrolyte is a substance that dissolves in water to give a solution that conducts electricity.

An electrolyte is a substance that dissolves in water to give a solution that conducts electricity. On dissolving electrolyte (polar in nature) in polar solvents, they get separated into its respective ions that are cations and anions, which are dispersed uniformly in the solvent. On applying electric potential to such solutions, the ions are drawn to the electrodes due to the abundance and deficiency of electrons on ions thus, resulting in conduction of electricity.

Interpretation Introduction

(f)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

The formation of ions takes place by the loss or gain of electron. The cation results from the loss of electron whereas the anion results from the gaining of electron by the atom.

Answer to Problem 42P

True.

Explanation of Solution

Given:

In a solution that conducts electricity, cations migrate towards the cathode and anions migrate towards the anode.

The loss of electron(s) from the atom results in the formation of cation and the gain of electron(s) by the atom results in the formation of anion. The cathode is negatively charged electrode whereas the positively charged electrode is anode. Since the unlike charges attract so, the cations which are positively charged will move towards negative electrode, cathode whereas the anions which are negatively charged will move towards positive electrode, anode.

Interpretation Introduction

(g)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

The formation of ions takes place by the loss or gain of electron. The cation results from the loss of electron whereas the anion results from the gaining of electron by the atom.

Answer to Problem 42P

True.

Explanation of Solution

Given:

Ions must be present in a solution for the solution to conduct electricity.

On dissolving electrolyte (polar in nature) in polar solvents, they get separated into its respective ions that are cations and anions, which are dispersed uniformly in the solvent. On applying electric potential to such solutions, the ions are drawn to the electrodes due to the abundance and deficiency of electrons on ions thus, resulting in conduction of electricity.

Interpretation Introduction

(h)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

The substances that do not dissociate into ions and thus, are non-conductor of electricity are said to be non-electrolytes.

Answer to Problem 42P

True.

Explanation of Solution

Given:

Distilled water is a nonelectrolyte.

Water in its pure form does not conduct electricity. The conduction of electricity takes place only due to the presence of ions. In distilled water, there are no such ions present which can conduct electricity thus, distilled water is a nonelectrolyte.

Interpretation Introduction

(i)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

A substance that dissolves in water to give a solution that conducts electricity is said to be an electrolyte.

Answer to Problem 42P

True.

Explanation of Solution

Given:

A strong electrolyte is a substance that completely dissociates into ions.

An electrolyte is a substance that dissolves in water to give a solution that conducts electricity. On dissolving electrolyte (polar in nature) in polar solvents, they get separated into its respective ions that are cations and anions, which are dispersed uniformly in the solvent. On applying electric potential to such solutions, the ions are drawn to the electrodes due to the abundance and deficiency of electrons on ions thus, resulting in conduction of electricity.

Interpretation Introduction

(j)

Interpretation:

To justify whether the given statement is true or false.

Concept Introduction:

A substance that dissolves in water to give a solution that conducts electricity is said to be an electrolyte.

Answer to Problem 42P

False.

Explanation of Solution

Given:

All compounds that dissolve in water are electrolytes.

All compounds that dissolve in water do not conduct electricity for example the sugar dissolves in water but the solution does not conduct electricity. Thus, for a solution to conduct electricity the dissociation of ions from the substance should takes place which result in the conduction of electricity.