The action of bleaching agent depends on hydrogen peroxide present in concentration more than
Answers
Answer:
Chlorine dioxide is about 10 times more soluble in water than hypochlorite. As such, it is widely used as a bleaching agent and is a potent antimicrobial chemistry.
Answer:
Major Areas of Use and Application
Bleaching agents are formulations that whiten or lighten a substrate by solubilizing color-producing substances or by altering their light-absorbing properties. Bleaching agents are used extensively in the pulp and paper industry, the textile industry, and commercial and household laundering.
The chemistry of bleaching agents is predominantly that of oxidizing agents: chlorine (Cl2) and some of its compounds or peroxygen species such as hydrogen peroxide (H2O2), ozone (O3), and sodium perborate (NaBO3). The decolorizing reaction generally involves the removal of chromophoric sites in which electron delocalization over conjugated double bonds has made the substrate capable of absorbing visible light. The bleaching agent will typically react by irreversibly cleaving or adding across these double bonds.
A few bleaching compounds act by chemical reduction; these include sulfur dioxide (SO2), sulfurous acid (H2SO3), hydrogensulfite (HSO3−), sulfite (SO32−), and dithionite (S2O42−), as well as sodium tetrahydroborate (borohydride) (NaBH4). Their application is primarily in pulp and textile manufacturing, where the bleaching action is thought to occur by reduction of a chromophoric carbonyl group. Other applications include the bleaching of glues, gelatin, soap, and food products.
Chemical bleaching of textiles (as opposed to bleaching by sunlight, a process known as crofting) had its advent soon after the discovery of the element chlorine by Scheele in 1774. Finding that aqueous solutions of chlorine gas weakened the fiber of textiles, Bertholet experimented with solutions of potassium hypochlorite (KOCl), made by dissolving chlorine gas in a solution of caustic potash (KOH). Labarraque made hypochlorite solutions industrially economic by replacing the more expensive caustic potash with caustic soda (NaOH). The liquid household bleach normally available today is a 5% solution of sodium hypochlorite (NaOCl).
Sterilants are strictly defined by the US Environmental Protection Agency as substances that totally destroy all forms of life, including viruses, bacteria, fungi, and their spores on inanimate surfaces, in water, or in the air. Many substances that render objects microbiologically safe for certain applications (i.e., reduce the level of living microorganisms below some predetermined level) are also commonly referred to as sterilants.
Sterilization can be accomplished by treatment with chemicals, as well as by heat, cold, and radiation. Chemical sterilants are also typically oxidizing agents, and their effectiveness is related to their ability to oxidize the cell wall of the microorganism and to diffuse through the cell wall and disrupt cellular activity. Many of the same substances that act as bleaching agents (Table 1) are also used extensively as sterilants