Who observed that in a mixture of non-reactive gases, the total gas pressure is equal to the sum of the partial pressures of the individual gases?

John Dalton

The correct answer is option 2. John Dalton.

The observation that in a mixture of non-reactive gases, the total gas pressure is equal to the sum of the partial pressures of the individual gases is credited to John Dalton.

John Dalton, an English chemist and physicist, formulated the law of partial pressures in the early 19th century. This law states that in a mixture of non-reactive gases, the total pressure exerted by the mixture is equal to the sum of the partial pressures of each gas in the mixture. It's one of the fundamental principles in the field of gas chemistry and is also known as Dalton's law of partial pressures.