In general chemistry, which of the following statements about water is false and does not correctly describe its properties?

Introduction / Context:
Water has many unusual properties that are important in chemistry and biology. These include hydrogen bonding, its role in photosynthesis, its ability to behave as both an acid and a base, and differences between normal water and heavy water. This question asks you to identify which statement is false and therefore does not accurately describe water.

Given Data / Assumptions:
- Hydrogen bonds in water are key to its high boiling point and other properties.
- Water participates in redox reactions such as photosynthesis.
- Heavy water contains deuterium instead of ordinary hydrogen.
- Water can donate or accept protons in acid base reactions.

Concept / Approach:
The crucial distinction in this question is between intramolecular and intermolecular hydrogen bonding. Intramolecular hydrogen bonding would occur within a single water molecule, while intermolecular hydrogen bonding occurs between different water molecules. In reality, hydrogen bonds in water are intermolecular. A hydrogen atom on one water molecule is attracted to the oxygen atom of a neighboring water molecule. The covalent bonds within each water molecule are not hydrogen bonds. Other statements must be checked against standard chemical knowledge, such as water being oxidized during photosynthesis and acting as both an acid and a base.

Step-by-Step Solution:
Step 1: Consider hydrogen bonding in water. Each water molecule can form hydrogen bonds with neighbors, but these are between molecules, not within a single molecule. Step 2: Recognize that the phrase intramolecular hydrogen bonding in water is incorrect, because the bonds inside a single water molecule are polar covalent bonds, not hydrogen bonds. Step 3: Recall that in the light reactions of photosynthesis, water is split and oxidized, releasing oxygen gas as a product. Step 4: Remember that ice made from heavy water has higher density than normal liquid water, so blocks of heavy ice can sink in normal water. Step 5: Know that water can behave as an acid by donating a proton or as a base by accepting a proton, which is called amphoteric behavior.

Verification / Alternative check:
Chemistry references describe hydrogen bonds in water as attractions between different molecules, explaining many bulk properties such as high surface tension and boiling point. Inside a single water molecule, there are only ordinary covalent bonds between hydrogen and oxygen. Photosynthesis equations always show oxygen gas being produced from water molecules. Acid base discussions use water as a classic example of a substance that can both donate and accept protons.

Why Other Options Are Wrong:
Option B: It is true that during photosynthesis, water is oxidized and oxygen gas is produced, so this statement is correct, not false.
Option C: Heavy water contains deuterium and has higher density than normal water. Ice of heavy water can sink in ordinary water, so this statement is also correct in general chemistry contexts.
Option D: Water is amphoteric and can act as both an acid and a base, which is a standard textbook fact.

Common Pitfalls:
Learners sometimes confuse intramolecular and intermolecular bonding terms or assume that any special bond involving hydrogen must be inside the molecule. Another common difficulty is remembering that heavy water behaves slightly differently from normal water, especially in density. Distinguishing clearly between interactions inside a molecule and between molecules is important for understanding hydrogen bonding.

Final Answer:
The correct answer is In condensed phases such as liquid water and ice, there is extensive intramolecular hydrogen bonding within each water molecule. because in reality hydrogen bonds in water occur between separate molecules, not within a single water molecule.