Which of the following statements is NOT true in regards to water, ethanol, and isopropanol?

A. Water has the highest boiling point.
B. Two lone pairs of electrons are assigned to the oxygen in each Lewis structure of all three molecules.
C. Dispersion forces affect all three molecules.
D. H-O-H and C-O-H bond angles are all equal to 1095 .
E. All of these are true.

What is your thinking? I will be happy to critique your thinking. Please refrain from posting under multiple names

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is it C?

To determine which statement is NOT true, let's analyze each option and how to determine the correctness of each statement.

A. Water has the highest boiling point.
To determine which substance has the highest boiling point, we need to compare the intermolecular forces between the molecules. The intermolecular forces in water are hydrogen bonding, while in ethanol and isopropanol, the intermolecular forces are hydrogen bonding as well as dispersion forces. Hydrogen bonding is stronger than dispersion forces. Therefore, the boiling point of water is higher than that of ethanol and isopropanol. Thus, statement A is true.

B. Two lone pairs of electrons are assigned to the oxygen in each Lewis structure of all three molecules.
To determine the number of lone pairs on the oxygen atom in each molecule, we need to draw their Lewis structures. Water (H2O) has two lone pairs of electrons on oxygen, ethanol (C2H5OH) has one lone pair of electrons on oxygen, and isopropanol (CH3CHOHCH3) also has one lone pair of electrons on oxygen. Therefore, statement B is NOT true.

C. Dispersion forces affect all three molecules.
Dispersion forces, also known as London dispersion forces, are present between all molecules. These forces occur due to temporary fluctuations in electron distribution, causing temporary-induced dipoles. Since water, ethanol, and isopropanol all have electrons, they all experience dispersion forces. Thus, statement C is true.

D. H-O-H and C-O-H bond angles are all equal to 1095.
To determine the bond angles in the molecules, we need to look at their molecular geometries. In water, the H-O-H bond angle is approximately 104.5 degrees due to the electron pair repulsion between the lone pairs on oxygen. In ethanol and isopropanol, the C-O-H bond angles are also less than 109.5 degrees due to similar electron pair repulsion. Therefore, statement D is NOT true.

E. All of these are true.
Since we have found that statement B and statement D are NOT true, we can conclude that statement E, which states that all of these statements are true, is NOT true.

Based on the analysis above, the statement that is NOT true is statement E.