Hydrogen peroxide (\(\rm H_{2}O_{2}\)) is not stored in a transparent vessel because it is sensitive to light, which can cause it to decompose into water (\(\rm H_{2}O\)) and oxygen gas (\(\rm O_{2}\)). This decomposition process can be accelerated by exposure to light, particularly ultraviolet (UV) light. 

To prevent this breakdown and maintain its effectiveness, hydrogen peroxide is typically stored in opaque or dark-colored containers that limit light exposure. Additionally, proper storage conditions help ensure its stability and prolong its shelf life.