SerGreen is right. Rubidium & water yields alkali and hydrogen gas. Also, when an acid and base react, it leaves water and a salt of some sort (eg. Sulfuric acid plus sodium hydroxide equals water and sodium sulfate). The salt that is produced is typically in solution int the water produced. So mabey acid/base interaction could leave salt-water.
EDIT: Not that the specific chemistry would need to be implemented. Just rubidium/water interaction (minus hydrogen) to produce base and base/acid interaction to produce salt-water.
Can we upgrade the stickman? Now we can add only 1 stickman at time controlled by arrows Im saying that if we can add 2 stickmans:1 controlled by arrows and the second controlled by W A S D A and D to move S to Spawn and W to Jump