Calculate gas pressure in a container where water and hot oil come together

(1) there is a container 1 m^3 in volume (2) there is 1 L of oil in the container, at 100 degrees celsius (3) there is 1 L of water in the container, at 20 degrees celsius (4) the water falls on top of the oil, and a reaction happens (5) gas pressure in the container increases following reaction What is the gas pressure in the container when the reaction finishes?