Filter paper is soaked in a sodium chloride solution and then dried. In the absence of light, this paper is dipped into a solution of silver nitrate and dried. A piece of money is placed on the paper, then everything is exposed to light. The coin is removed ...
- In the absence of light, there is formation of silver chloride: $Ag^+$ $+$ $Cl^-$ $\longrightarrow$ $Ag^+Cl^-$ - The light causes an internal redox silver chloride $2Ag^+$ $+$ $Cl^-$ $\longrightarrow$ $2Ag$ $+$ $Cl_2$ (Simplified equation, we will see later things in detail) Thus the paper exposed to light takes the gray colour of silver metal!
Author: → Franklychemistry
From left to right you saw: - Silver chloride (white) - Silver bromide (creamy white) - Silver iodide (yellowish white) The three substances were exposed to daylight: The photosensitivity of the silver halides is quite different. - Silver chloride and bromide are very photosensitive. - The silver iodide is only weakly photosensitive!