Question

1. what important gas is released when water is split? type a response

Explanation:

When water ($H_2O$) is split (e.g., via electrolysis or photolysis), the chemical reaction is $2H_2O
ightarrow 2H_2 + O_2$. The important gas released here is oxygen ($O_2$), and also hydrogen ($H_2$), but oxygen is crucial for respiration and many biological/industrial processes.

Answer:

Oxygen (and Hydrogen; but Oxygen is a key important gas released, along with Hydrogen. Primarily, Oxygen (or $O_2$) is a vital gas released when water is split, along with Hydrogen ($H_2$). However, the most commonly referred important gas in this context (especially for biological/atmospheric importance) is Oxygen.)