Which of the following statements is NOT true in regards to water, ethanol, and isopropanol?
A. Two lone pairs of electrons are assigned to the oxygen in each Lewis structure of all three molecules.
B. Dispersion forces affect all three molecules.
C. H-O-H and C-O-H bond angles are all equal to 1095.
D. Water has the highest boiling point.
E. All of these are true.
I helped, with Dan H, to answered this question yesterday or at least a similar one. A is true, B is true, C is not true, D is true, E is not true.
To determine which statement is NOT true, let's analyze each statement:
A. Two lone pairs of electrons are assigned to the oxygen in each Lewis structure of all three molecules.
To verify this statement, we can draw the Lewis structures of water, ethanol, and isopropanol. Water (H2O) has two lone pairs of electrons on the oxygen atom, ethanol (CH3CH2OH) has one lone pair of electrons on the oxygen, and isopropanol (CH3CHOHCH3) also has one lone pair of electrons on the oxygen. Therefore, this statement is NOT true for ethanol and isopropanol.
B. Dispersion forces affect all three molecules.
Dispersion forces, also known as London dispersion forces or van der Waals forces, are temporary attractive forces between the electrons of one molecule and the nucleus of another molecule. They exist in all molecules, including water, ethanol, and isopropanol. Therefore, this statement is true.
C. H-O-H and C-O-H bond angles are all equal to 109.5°.
The H-O-H bond angle in water (H2O) is approximately 104.5° due to the presence of two lone pairs of electrons on the oxygen atom. The C-O-H bond angle in ethanol and isopropanol is close to 109.5° due to the tetrahedral arrangement of the atoms around the carbon atom. Therefore, this statement is NOT true.
D. Water has the highest boiling point.
The boiling point of a substance is influenced by intermolecular forces. Water molecules are capable of forming hydrogen bonds, which are stronger than the dispersion forces present in ethanol and isopropanol. As a result, water has a higher boiling point than ethanol and isopropanol. Therefore, this statement is true.
E. All of these are true.
Since we identified that statements A, C, and E are not true, we can conclude that statement E is NOT true.
Therefore, the correct answer is E. All of these statements are not true.