The time it takes for antacids to dissolve in hot water can vary based on several factors, including the type of antacid, its formulation (chewable tablets, powders, etc.), the temperature of the water, and the specific ingredients in the antacid. Generally, antacids that are in powder form dissolve more quickly than tablets.
As a rough estimate, most effervescent antacids can start to dissolve quickly, often within a few minutes (usually around 2 to 5 minutes), especially in hot water. Chewable tablets may take longer to fully dissolve, potentially around 5 to 10 minutes or more, depending on the size and formulation.
It's a good idea to stir the mixture to aid in the dissolution process. If you have a specific type of antacid in mind, I can provide more tailored information!