Study the reaction scheme below in which compound Y is produced by the reaction of compound X with water - Leaving Cert Chemistry - Question 8 - 2021

Y is classified as a secondary alcohol because the hydroxyl (OH) group is attached to a carbon atom that is bonded to two other carbon atoms (the C-2 carbon in the structure). Thus, it does not belong to the primary category where the OH group would be bonded to a carbon that has only one other carbon attached.

Z is propan-1-ol, also known as n-propanol or simply propanol.

The expanded molecular structure for Y is as follows:

       H   H
        |   |
    H - C - C - OH
        |   |
       H   H

In this structure, the carbon atoms are connected by single bonds and the -OH group is shown clearly. When Z is reduced, a hydrogen atom is added to the carbon that previously had a double bond.

In Z (propan-1-ol), the carbon atom that is involved in the reduction changes its hybridization from sp2 to sp3 as it gains a hydrogen in the reduction process. As a result, the geometry changes from trigonal planar (approximately 120° bond angles) to tetrahedral geometry (approximately 109.5° bond angles).

The conversion of X to Y involves a hydrogenation reaction, which is characterized by the addition of hydrogen across a double bond.

Another product of the reaction of X with water is an alcohol (specifically, an alcohol arising from hydrolysis).

The balanced equation for the reaction of Y (propan-2-ol) with sodium is:

$\text{2 C}_3\text{H}_8\text{O} + 2\text{Na} \rightarrow 2\text{C}_3\text{H}_7\text{ONa} + \text{H}_2$

To find the concentration in moles per liter, we calculate:

A hand sanitizer labeled 70% (v/v) contains 70 mL of isopropyl alcohol in 100 mL of solution. The density of isopropyl alcohol is about 0.785 g/mL. Therefore:

$70 \text{ mL} \times 0.785 \text{ g/mL} = 54.95 \text{ g of isopropyl alcohol}$

The molar mass of isopropyl alcohol is approximately 60.1 g/mol, so:

$\frac{54.95 \text{ g}}{60.1 \text{ g/mol}} \approx 0.914 \text{ moles}$

This results in a concentration of approximately 0.914 moles in a total volume of 0.1 L, thus the concentration is:

$\frac{0.914 \text{ moles}}{0.1 \text{ L}} = 9.14 \text{ M}$

The most influential type of intermolecular force that occurs in Z (propan-1-ol) is hydrogen bonding. Due to the presence of the hydroxyl group (-OH), propan-1-ol can form strong hydrogen bonds with other molecules, which significantly affects its physical properties such as boiling point and solubility.