Through a process known as electrolysis, water can be split into hydrogen and oxygen. What type of reaction is this? Give an explanation for your choice.

Electrolysis of water is the decomposition reaction, because from one molecule (water) two molecules (hydrogen and oxygen) are produced. Water is separeted into two molecules:

Reaction of reduction at cathode: 2H⁺ (aq) + 2e⁻ → H ₂ (g).

Reaction of oxidation at anode: 2H ₂ O (l) → O ₂ (g) + 4H ⁺ (aq) + 4e ⁻.