State the formula relating pressure of a gas with its mole fraction in a liquid solution in contact with it.

Explanation

To solve the question regarding the formula that relates the pressure of a gas with its mole fraction in a liquid solution in contact with it, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Context**: We need to relate the pressure of a gas to its mole fraction in a liquid solution. This relationship is described by Henry's Law.

2. **Henry's Law Statement**: According to Henry's Law, the partial pressure of a gas in a solution is directly proportional to the mole fraction of that gas in the solution.

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