What happens to water molecules as electricity passes through them that makes electrified water so deadly?

Question

And part 2: as soon as the electrical current is removed, does the water become immediately safe to touch again?

In: Chemistry

Answer 1

Electricity passing through water doesn’t make the water itself harmful, it is the electricity that is the danger. Our bodies use charge gradients between cells to transfer signals through nerves, and electricity is a massive charge gradient. The result is that when electricity passes through the human body it triggers all kinds of signals at once; muscles contract all at once without stopping, senses go haywire, etc. This can be extremely dangerous for things that we need to operate constantly, such as our heart.

Beyond that, electricity experiences resistance in all substances (except superconductors) and that resistance results in heat. Sufficient electricity passing through the body can produce enough heat to damage tissue through actually cooking it, denaturing proteins and chemically altering it permanently. Essentially it is a penetrating burn wherever the path of electricity flowed.

So electricity has the potential to be really bad for the human body, but why is it so dangerous with water? This is because normally electricity is confined to things like wires, and as long as you don’t touch a hot wire you should be good. Water can conduct electricity though (technically it needs some trace salts or similar ions to be a good conductor, but that is usually the case unless it is highly distilled water). This turns a dangerous wire into a pool of dangerous fluid that covers a much larger area and can flow around in unexpected ways. It is also often not obvious the electrified water is dangerous since it just looks like normal water, but touching it could result in lethal path for electricity to move to ground though your body.

And yes, if the electricity is removed then the water is immediately safe to touch (as long as it isn’t hot). Think about if you cut the electricity to a wire, the wire is immediately safe to touch because it wasn’t somehow altered into a harmful material while it was conducting electricity.