Chapter 14, Problem 28A

(a)

Interpretation Introduction

Interpretation:

The substance in the given pair with lower boiling point is to be predicted.

Concept Introduction :

Boiling point is a temperature at which pressure exerted by surrounding on the liquid is equal to the vapor pressure of the liquid. In a liquid molecules or atom are close contact, the thermal energy are required to overcome the attraction between them. The attraction is nothing but intermolecular forces between them. The strength of inter molecular forces are, $\text{ion - ion > H - bonding > dipole - dipole > london dispersion}$ . The compound with strong inter molecular force, its required higher thermal energy. So it is higher boiling point.

Answer to Problem 28A

The compound ${\text{CH}}_{\text{3}}\text{OH}$ is with lower boiling point.

Explanation of Solution

The given pair is ${\text{CH}}_{\text{3}}\text{OH}$ and ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ with same functional group alcohol. The $\text{OH}$ group from the compound shows intermolecular H bonding. So the given pair shows intermolecular H bonding and London dispersion force. The boiling point increases as the molecular mass of the alcohol increases. In the given pair of compounds, molecular mass of ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ is higher than ${\text{CH}}_{\text{3}}\text{OH}$ . So ${\text{CH}}_{\text{3}}\text{OH}$ is lower boiling point than ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$ .

(b)

Interpretation Introduction

Interpretation:

The substance in the given pair with lower boiling point is to be predicted.

Concept Introduction :

Boiling point is a temperature at which pressure exerted by surrounding on the liquid is equal to the vapor pressure of the liquid. In a liquid molecules or atom are close contact, the thermal energy are required to overcome the attraction between them. The attraction is nothing but intermolecular forces between them. The strength of inter molecular forces are, $\text{ion - ion > H - bonding > dipole - dipole > london dispersion}$ . The compound with strong inter molecular force, its required higher thermal energy. So it is higher boiling point.

Answer to Problem 28A

The compound CH3CH3 is with lower boiling point.

Explanation of Solution

The given compound ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{3}}$ is simple alkane and ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{OH}$ with alcohol functional group. Simple alkane shows only London dispersion force as inter molecular force and the ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{OH}$ compound with $\text{OH}$ group which have strong inter molecular H bonding. Hence ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{OH}$ have intermolecular H bonding and London dispersion force. The compound ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{OH}$ requires higher energy to boil than ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{3}}$ . So ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{3}}$ is lower boiling point than ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{OH}$ ..

(c)

Interpretation Introduction

Interpretation:

The substance in the given pair with lower boiling point is to be predicted.

Concept Introduction :

Boiling point is a temperature at which pressure exerted by surrounding on the liquid is equal to the vapor pressure of the liquid. In a liquid molecules or atom are close contact, the thermal energy are required to overcome the attraction between them. The attraction is nothing but intermolecular forces between them. The strength of inter molecular forces are, $\text{ion - ion > H - bonding > dipole - dipole > london dispersion}$ . The compound with strong inter molecular force, its required higher thermal energy. So it is higher boiling point.

Answer to Problem 28A

The compound CH4 is with lower boiling point.

Explanation of Solution

The given compound ${\text{CH}}_{\text{4}}$ is simple alkane and ${\text{H}}_{\text{2}}\text{O}$ . Simple alkane shows only London dispersion forces as intermolecular force and the ${\text{H}}_{\text{2}}\text{O}$ compound with two $\text{OH}$ groups which have strong inter molecular H bonding. Hence ${\text{H}}_{\text{2}}\text{O}$ have strong intermolecular H bonding and London dispersion force. ${\text{H}}_{\text{2}}\text{O}$ Require higher energy to boil than ${\text{CH}}_{\text{4}}$ . So ${\text{CH}}_{\text{4}}$ is boiled at lower temperature than ${\text{H}}_{\text{2}}\text{O}$ .

(d)

Interpretation Introduction

Interpretation:

The radioisotope should be defined and described

Concept Introduction:

There can be different versions of a different element in the nature these versions are called isotopes.

Answer to Problem 28A

Radioisotope: It is the isotope or a chemical version of an element that has an unstable nucleus, this specie can go through a radioactive decay.

Explanation of Solution

The radioactive isotope of an element is radioisotope having unstable nucleus. It’s also produced artificially as well as naturally. Due to excess energy of nucleus, newly created radiation particle is imparted. Gamma rays and subatomic particles are emitted from the radioactive isotope as it undergoes radioactive decay.