Question

Give an example of each of the following chemical reactions.
A photochemical reaction involving
$\left(i\right)$ Silver salt
$\left(ii\right)$ Water

Answer 1

Hint: A chemical reaction which occurs due to light is called a photochemical reaction. The beautiful world around us is able to see this just because of the photochemical reaction which is taking place in the retinal: a molecule which is a photoreceptor named rhodopsin changes shape after absorbing the light.

Complete answer:
The light is being absorbed by the molecules and forming excited states which have different properties compared to the original molecule. Photochemical reactions play a very important role in our life. the process name as photosynthesis upon which all life depends. A photochemical reaction depends upon the structure of the compound, intensity of light and presence of other reactants. When the molecule absorbs the light, the energy of the electrons rises to a point and then it will undergo chemical reaction.
$\left(i\right)$Here now we have to write a reaction which involves silver salt.
$$AgC{l}_2\stackrel{\mathrm{\Delta }}{\to }Ag+C{l}_2$$
Here silver chloride is a silver salt which reacts with light and gets decomposed into metallic silver and chlorine gas. So, this is a photochemical reaction.
$\left(ii\right)$ $6C{O}_2+6H_{2}O\to C_6{H}_{12}{O}_6+6O_2$
This is the photosynthesis reaction. The plants absorbed the sunlight and then converted the energy into carbohydrates by the help of water and carbon dioxide and releasing oxygen in the surrounding which is the byproduct.

Note:
Photochemical process used:
-Xerography
-Photography
-Semiconductor chips
-Printing newspapers
-We need vitamin D for bones and teeth, which formed on the skin of animals after exposure to sunlight.
-Ozone layer which is present in the stratosphere, is formed by the photochemical decomposition. So photochemical processes are present in our surroundings.