Chapter 11, Problem 1KSP

Which of the following would you expect to be more soluble in water than in benzene? (Select all that apply.)

(a)

${\text{CH}}_{\text{3}}\text{OH}$

(b)

${\text{CCl}}_{\text{4}}$

(e)

$\text{Kl}$

Interpretation Introduction

Interpretation:

The compounds that is more soluble in water than benzene is/are to be identified.

Concept introduction:

The various kinds of interactions that bind a molecule are known as intermolecular forces. These can be dispersion, dipole–dipole, ion–dipole,and hydrogen bonding.

The solubility of a compound depends on the intermolecular forces present. Apolar solvent is soluble in apolar solvent only. A compound is soluble in water only when it is able to form hydrogen bonds with it.

Answer to Problem 1KSP

Solution: The correct answersareoption (a) and option (e).

Explanation of Solution

Reason for the correct option:

The molecule, methanol $\left({\text{CH}}_3\text{OH}\right)$,is a polar molecule. This is so due to the presence of an oxygen atom, which gives rise to polarity and a permanent dipole moment. Thus, dipole–dipole forces are present. The presence of $\text{O}-\text{H}$ bonds enables it to participate in hydrogen bonding.

Thus, it is soluble in water more readily. On the other hand, benzene is a nonpolar molecule. So, methanol is insoluble in benzene.

Potassium iodide $\left(\text{KI}\right)$ is a polar molecule that is ionic in nature. It is, therefore, soluble in water and extremely less soluble in benzene. So, this option is incorrect.

Hence, option (a) and option (e) are correct.

Reasons for the incorrect options:

Option (b) is incorrect because ${\text{CCl}}_4$ is a nonpolar molecule. So, it is insoluble in water but is soluble in benzene. So, this option is incorrect.

Option (c) is incorrect because trans-dichloroethene is a nonpolar molecule. It is insoluble in water. So, this option is incorrect.

Option (d) is incorrect because cis-dichloroethene is a polar molecule but it is unable to form hydrogen bonds in water. It is, therefore, insoluble in water. So, this option is incorrect.

Hence, options(c) and (d) are incorrect.