Chapter 10, Problem 10.44AP

(a)

Interpretation Introduction

Interpretation:

The type of bonding present in potassium iodide $\text{(KI) }$ and pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ has to be explained.

Concept Introduction:

Bonding:

The bonds are formed by sharing and transfer of one or more electrons present in a molecule.  The atoms or ions present in a molecule are bonded together.  The bonds can be formed as single, double and triple bonds.  The bonds can be formed based on electronegativity value.  There are few examples of bonds are given.

They are,

• Ionic bond: When electrons are transferred from metal atom to nonmetal atom, and as a result of interaction between oppositely charged ions and forms ionic bond.  These types of bonds are known as ionic bonds.
• Covalent bond: These bonds are formed due to electrostatic attraction between atoms and its shared pair of electron.  These bonds can able to choose their octet fill by sharing electron pairs between them.  These are known as covalent bonds.
• Metallic bond: The metallic bonds are formed between ionized atoms of metal and the sea of electrons is present around them.  The metal compounds generally have low electronegativity.  It can be easily ionized and they can lose the outermost electron. 

Electronegativity: The ability of atom to attract bonding pair of electrons is known as electronegativity.  The electronegativity can be denoted as $\text{χ}$.

Explanation of Solution

The potassium iodide $\text{(KI)}$ compound forms an ionic bond.  The elements potassium and iodine have different electronegativity.  The compound potassium iodide $\text{(KI)}$ is an inorganic compound.  Hence potassium iodide $\text{(KI)}$ forms an ionic bond.

The compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ is an organic compound.  The pentane compound forms covalent bond.  It is a strong bond formed between atoms.  Hence the given compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ forms covalent bond between bonds.

(b)

Interpretation Introduction

Interpretation:

The compound potassium iodide $\text{(KI)}$ and pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ in that solubility in water has to explained.

Concept Introduction:

Solubility:

The solubility is defined as the solid or liquid or gaseous substance which dissolves in suitable solvent.  The solubilty of compounds also based on polar or nonpolar molecules.  The nonpolar molecule has no separate positive and negative charge.  Polar molecules have separate positive and negative charges.

Explanation of Solution

The compound potassium iodide $\text{(KI)}$ is soluble in water.  The water is known as a polar molecule.  The compound potassium iodide $\text{(KI)}$ can be separated as ${\text{k}}^{\text{+}}{\text{I}}^{\text{-}}$ ions and it is a polar molecule.  Hence it is highly soluble in water.

The compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ is insoluble in water.  The pentane compounds are nonpolar molecules.  The water molecules are best example for polar molecules.

(c)

Interpretation Introduction

Interpretation:

The compound potassium iodide $\text{(KI)}$ and pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ solubility in organic solvents has to be explained.

Concept-Introduction:

Refer: (b)

Explanation of Solution

The compound potassium iodide $\text{(KI)}$ is a polar molecule.  It can be soluble in polar organic solvents.  The organic solvents like ethanol which is a nonpolar molecule.  The potassium iodide can be soluble in organic solvents like ethanol.  Hence the compound

Potassium iodide $\text{(KI)}$ is soluble in organic solvents.

The compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ is a nonpolar molecule.  Most of the organic solvents are nonpolar molecules.  Hence the compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ is soluble in organic solvents.

(d)

Interpretation Introduction

Interpretation:

The melting point of given compound potassium iodide $\text{(KI)}$ and pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ has to be explained.

Explanation of Solution

The melting point of potassium iodide $\text{(KI)}$ is high.  The reason for high melting of potassium iodide, it belongs to ionic bonds.  The compounds potassium iodide $\text{(KI)}$ is held together by ionic bond.  The increased surface area increases the force of attraction between molecules and this result in raising melting point.  So the potassium iodide $\text{(KI)}$ has high melting point.

The compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ has melting point.  The melting point is increased, depends on the number of carbon present in the organic compound.  As number of carbon increases the melting point also increased.

(e)

Interpretation Introduction

Interpretation:

The boiling point of given compound potassium iodide $\text{(KI)}$ and pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ has to be explained.

Explanation of Solution

The boiling point of potassium iodide $\text{(KI)}$ is high.  The compounds potassium iodide $\text{(KI)}$ is held together by ionic bond.  The increased surface area increases the force of attraction between molecules and this result in raising boiling point.  So the potassium iodide $\text{(KI)}$ has high boiling point.

The compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ has boiling point.  The boiling point is increased, depends on the number of carbon present in compound.  As number of carbon increases the boiling point also increases.  The number of carbon present in pentane is five carbon atoms.  The compound pentane ${\text{(CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{)}$ has high boiling point.