Final answer:
Chlorine water is pale green primarily because of the natural color of chlorine gas. The substances such as sodium hypochlorite used for water treatment still maintain this color, revealing the characteristic pale greenish tint when dissolved in water.
Step-by-step explanation:
The pale green color of chlorine water is primarily due to the natural color of chlorine gas. Chlorine itself is a pale yellow-green gas, which, when dissolved in water, gives the water a pale greenish hue. This is the characteristic color of chlorine as observed in its gaseous state. When added to water for purification or as a disinfectant, chlorine can form various compounds, such as sodium hypochlorite or chloramines, through reactions with other elements or organic substances. However, the color we associate with chlorine water is largely attributed to the chlorine itself, not the formation of these compounds or the interaction with light.
It's important to note that the chlorine used in water treatment is often not in its pure elemental form but in the form of compounds like sodium hypochlorite or chloramine that result from adding chlorine to the water. These compounds are effective in killing bacteria and removing other biological contaminants, keeping the water safe for human use.