Bleach in water only good for one day? In this time of COVID-19 our establishment is being told by government sources to spray down surfaces with a 9:1 water bleach solution, and then told to throw it out within 24 hours. What makes it less effective when we have over the counter products with bleach in them that obviously sit on the shelves for months and years?
Commercial liquid chlorine bleaches, used in the laundry, are stabilized with sodium hydroxide at high pH. When you dilute the bleach in water, the alkali concentration also decreases. As a result, the active ion (hypochlorite $\ce{OCl-}$) slowly begins to decompose to the chloride ion (the common salt).