Explain the process of photolysis of water with suitable diagram.

Explanation

The process of Photolysis is associated with Oxygen Evolving Complex in pigment system II and is catalysed by the presence of `Mn^( + +)` and `Cl^-`. When the pigment system II is active it receives light and the water molecule splits into `OH^(-)` ions and `H^+` ions. The `OH^-` ions unite to form water molecules again and release `O_2` and electrons. Photolysis of wateris due to strong oxidant which is yet unknown and desigted as Z or Yz. Widely accepted theory proposed by Kok et al., (1970) explaining photo-oxidation of water is water oxidizing clock (or) S. State Mechanism. It consists of a Series of 5 states called as `S_0, S_1, S_2, S_3` and `S_4`. Each state acquires positive charge by a photon (hv) and after the `S_4` state it acquires 4 positive charges, four electrons and evolution of oxygen. Two molecules of water go back to the `S_0`. At the end of photolysis 4 `H^+, 4 e^- and O_2` are evolved from water.