Under what natural conditions can sunlight decompose water?

Sunlight can decompose water under natural biological conditions. For example, the oxygen needed by animals in the ocean comes not only from dissolved oxygen in water, but also from oxygen obtained by animals themselves decomposing water.

The spectral range of surface illumination depends on the influence of the atmosphere on the height of the sun. The dusk around sunrise and sunset depends on the blue spectral components dominated by atmospheric scattering, while red light dominates the color of sunrise and sunset. These effects are obvious in natural light photography, because natural light is sunlight through atmospheric media in principle.

Extended data:

Weak acid radical or weak base ion reacts with water to generate weak acid and hydroxide ion (OH-) (or weak base and hydrogen ion (H+)). Hydrolysis of organic matter is widely used in industry, mainly producing alcohol and phenol.

Hydrolysis is the reverse reaction of neutralization or esterification. The hydrolysis of most organic compounds is difficult to be carried out smoothly only with water, usually under alkaline or acidic conditions.

In acidic aqueous solution, fat will be hydrolyzed into glycerol and fatty acids; Starch will be hydrolyzed into maltose, glucose and so on. Protein will be hydrolyzed into amino acids and other substances with relatively small molecular weight.

In alkaline aqueous solution, fat will be decomposed into glycerol and solid fatty acid salts, that is, soap, so this hydrolysis is also called saponification.

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