At a constant temperature, the amount of dissolved gas in a liquid is proportional to the partial pressure of the gas above the liquid". This law is known as

Henry's Law

The correct answer is option 1. Henry's Law.

The law described, stating that "the amount of dissolved gas in a liquid is proportional to the partial pressure of the gas above the liquid," is known as Henry's Law.

Henry's Law governs the solubility of gases in a liquid and describes the relationship between the concentration of a dissolved gas and its partial pressure in the gas phase above the liquid. According to Henry's Law, at a constant temperature, the concentration of a dissolved gas is directly proportional to its partial pressure in the gas phase.