Final answer:
Dehydration synthesis, also known as a condensation reaction, is a chemical process where two molecules combine and release water as a byproduct. Composition reactions such as the combination of hydrogen gas and oxygen gas to form water also result in water as an end product.
Step-by-step explanation:
A reaction that results in the formation of water as an end product is commonly observed in dehydration synthesis, which is also known as a condensation reaction. During dehydration synthesis, two molecules combine by releasing water; specifically, one molecule contributes a hydrogen atom (H) and another contributes a hydroxyl group (OH), and together they form a molecule of water (H2O) as a byproduct. An example of such a reaction would be the synthesis of complex carbohydrates from simpler ones. Additionally, composition reactions can also produce water, as seen in the reaction between hydrogen gas (H2) and oxygen gas (O2) to form water:
2 H2(g) + O2(g) → 2 H2O(l)
This type of reaction is integral to various biochemical processes, including the formation of polymers like proteins and nucleic acids from their respective monomers.