What happens during the chemical reaction of water and calcium sulfate in alginate?

During the chemical reaction of water and calcium sulfate in alginate, the process primarily involves the transformation of the mixture into a gel or solid state, which is crucial for its function in dental procedures. This occurs because calcium sulfate acts as a reactant that interacts with the alginate powder for an ionic cross-linking reaction when water is added.

When the alginate is mixed with water, the alginate powder absorbs water and swells. The calcium ions released by calcium sulfate then bind with the alginate chains, forming a three-dimensional network. This network effectively traps the water, resulting in the formation of a gel. The gel state is what gives alginate its ability to hold shape and provide accurate impressions of dental structures.

The other options, such as becoming a liquid or evaporating, do not accurately describe the behavior of alginate upon mixing with water. The formation of bubbles could potentially occur if there is vigorous mixing; however, it is not a fundamental characteristic of the alginate setting process. The core reaction centers on the development of a gel structure, which is essential for its application in dentistry, thus confirming that the correct answer focuses on its transition to a gel or solid state.