__ H2O + ___02 → _H2O2

2H2O + 1O2 → 2H2O2

Explanation:

by semiractions:

(1)      2 H2O  →  H2O2  + 2H+

(2)      2H+  +  O2  →   H2O2

(1) + (2):

⇒ 2H2O + O2   →   2H2O2

                     4 - O - 4

                     4 - H - 4

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.