This question presents a bit of a paradox. You're asking about the solubility of a gas in water if the volume is *decreased* but *remains constant*. Here's why this doesn't quite make sense and how to think about the relationship between gas solubility and volume:

* Volume can't decrease and remain constant simultaneously. These are opposing concepts.

* Solubility is affected by pressure, not just volume. When we talk about gas solubility, we're really interested in the pressure exerted by the gas above the liquid.

Here's the correct way to understand the relationship:

* Decreasing the volume of a container holding a gas *increases* the pressure. This is based on Boyle's Law (P₁V₁ = P₂V₂).

* Increasing the pressure *increases* the solubility of a gas in water. This is Henry's Law, which states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.

In summary: If you decrease the volume of a container holding a gas, you increase the pressure, and this *increases* the solubility of the gas in water.