These systems rely on a process called positive feedback to stay locked in place. In these reactions, a newly formed product actually helps create more of itself. This unique self creation process is known as an autocatalytic reaction.
Because the product speeds up its own birth, the whole system stays strongly in one state. To make the system switch, you must push it hard past a critical tipping point. Once it finally flips to the second state, it strongly locks into that new setup.
Getting it to flip back requires a completely different amount of effort or temperature. This weird one way resistance is known in physics as hysteresis. Hysteresis means the path forward looks very different from the path backward.
This switchable behavior is incredibly important for creating natural chemical clocks and timers. It also plays a massive role inside living human biology and single cells. Cells use bistable chemical reactions to build genetic switches and store tiny chemical memories.
A common student mistake is thinking these reactions just stop when they reach a stable state. In reality, the chemicals are still reacting furiously to hold that perfect stable balance.