What Happens in Water Solutions
When you're doing electrolysis with aqueous solutions, things get more interesting because water (H₂O) splits into hydrogen ions (H⁺) and hydroxide ions (OH⁻). This means you've got more options at each electrode!
At the cathode, you're choosing between the metal ion and the hydrogen ion. If your metal is more reactive than hydrogen (think sodium or magnesium), then hydrogen gas bubbles off instead of the metal forming. It's like hydrogen is pushing in front of the queue!
At the anode, you're deciding between the hydroxide ion and whatever other negative ion is floating about. If hydroxide ions get discharged, you'll see oxygen gas being produced.
This choice system is crucial for predicting what products you'll get. The more reactive the metal, the more likely you are to get hydrogen gas at the cathode rather than the actual metal.
Remember: More reactive metals = hydrogen gas produced instead of the metal itself!