Question

Select the intermolecular force(s) present in a liquid sample of each compound.

Answer 1

a) Dispersion forces

The alkanes with atoms of C and H, which have not a substantial diference in electron affinity, do not exhibit regions with more electron density than others.

In this case the only forces that atract one molecule to other are the dispersion forces, which is due to temporal dipoles. Dispersion forces are the weakest intermolecular forces.

b) Dipole - dipole interactions

The double bond C = O of the molecule is highly polar, which creates permanent dipoles and so dipole - dipole interactions.

c) Hydrogen bonding

The large electronegativity difference between H and O create a strong polar bond. The  small hydrogen atom that is slightly positively charge interacts with the unshared electron pairs of oxygens from a close molecule forming hydrogen bonding.

This is the strongest intermolecular force.

Answer 2

a) The intermolecular forces present in ${\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_3}$ are $\boxed{{\text{dispersion forces}}}$.

b) The intermolecular forces present in ${\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{CHO}}$ are $\boxed{{\text{dipole - dipole interactions}}}$.

c) The intermolecular force present in ${\text{C}}{{\text{H}}_{\text{3}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{OH}}$ is  .

Further Explanation:

Intermolecular forces (IMF) are the forces present between atoms or molecules. Such forces can be attractive or repulsive in nature.

Types of IMF

1. Dipole-dipole attraction

These types of forces exist between the two dipoles. A dipole is characterized by two opposite charges separated by some distance in between them. The positive end of one dipole interacts with the negative end of another dipole. HF shows this type of intermolecular force.

2. Ion-dipole forces

Such forces exist between an ion and a dipole. Ion can be positively or negatively charged and dipole consists of a pair of oppositely charged ions.

3. Ion-induced dipole forces:

As is evident from its name, this force arises when an ion induces a dipole in a non-polar molecule. Due to this, the arrangement of electrons in the non-polar molecule gets disturbed.

4. Dispersion forces:

Atoms and molecules have such forces in between them. This is also known as Vander Waals forces or London forces.

5. Hydrogen bonding:

This force comes into account when there is a presence of a hydrogen atom and a highly electronegative element. Nitrogen, oxygen, and fluorine are highly electronegative atoms and thus are capable to form hydrogen bonds in presence of hydrogen.

a) ${\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_3}$ is a hydrocarbon with four carbon atoms. There is a slight difference in the electronegativities of both carbon and hydrogen atoms so it is non-polar in nature. Therefore dispersion forces exist in this molecule.

b) In ${\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{CHO}}$, there is a presence of electronegative oxygen atom due to which this molecule is polar in nature. Therefore dipole-dipole interactions are present in this molecule.

c) In ${\text{C}}{{\text{H}}_{\text{3}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{OH}}$, the highly electronegative oxygen atom forms hydrogen bonding with the hydrogen atom. Therefore hydrogen bonding exists in this molecule.

Learn more:

1. Number of covalent bonds formed by nitrogen: https://brainly.com/question/6029316

2. Which pair will form a covalent bond?: https://brainly.com/question/1126757

Answer details:

Grade: Senior School

Chapter: Intermolecular forces

Subject: Chemistry

Keywords: intermolecular forces, hydrogen bonding, dispersion forces, dipole-dipole attraction, ion-induced dipole, ion-dipole forces, CH3CH2CH2CH3, CH3CH2CHO, CH3CH2CH2OH.