What is the relationship between bleaching and oxidative bleaching of sodium peroxide?

Common bleaching agents are SO2, HCl, CA(CLO2)2, Na2O2, H2O2, ozone, activated carbon (or charcoal), etc. Its bleaching essence belongs to the following three categories: 1. Combined with organic pigments to form an unstable colorless substance, SO2 is introduced into the magenta solution, and the solution fades.

When heated, the solution turns red again. The essence of SO2 bleaching is that the H2SO3 formed by the reaction of SO2 with water combines with organic pigments to form unstable colorless compounds, which can return to their original color when exposed to light, heat or long-term storage. This is why straw hats that have been bleached with sulfur dioxide gradually turn yellow over time.

The principle of SO2 bleaching is a non-oxidation-reduction reaction. 2. Oxidative bleaching: Bleach has oxidizing properties and oxidizes organic pigments into stable colorless substances.

1) Bleaching of chlorine water and Ca(CLO2): Dry chlorine gas can not fade the red cloth strips, but can fade the wet red cloth strips, which proves that it is not Cl2 that plays a bleaching role, but HCl. Chlorine can also fade the magenta solution, but it cannot be restored by heating, and its essence is a redox reaction.

Ca(clo)2 is easily hydrolyzed in water, or reacts with CO2 to form HCOs, thus exhibiting bleaching: Ca(clo)2+2H2O=Ca(OH)2+2HCO, Ca(clo)2+H2O+CO2=CaCO3 +2HCOs. Taking advantage of their strong oxidizing properties, HClo is often used for tap water disinfection, and Ca(clo)2 reacts with CO2 and water to form HCl, which is bleaching, and is often used for bleaching clothes and fabrics.

2) Bleaching of H2O2 and Na2O2: hydrogen peroxide can automatically decompose at room temperature: 2H2O2 = 2H2O + O2, so it is a strong oxidizing agent, and it is commonly used as a bleach agent in the textile industry, which is to use its oxidation.

Na2O2 is a yellowish crystal that, when combined with water or dilute acid, produces hydrogen peroxide and violently exothermics. The generated H2O2 immediately separates and releases oxygen when heated, showing strong oxidation: 2Na2O2+2H2O=4NaOH+O2.

Therefore, Na2O2 is an important industrial bleaching agent. (3) Bleaching of ozone: O3 molecule is unstable, the oxidation capacity is much stronger than O2, and it has strong oxidation in aqueous solution.

So, when water is present, O3 is a strong bleaching agent and is also used for water and air disinfection. 3. Adsorption bleaching: charcoal and activated carbon have a loose and porous structure, forming a large specific surface area and having strong adsorption.

Activated carbon can be used as a decolorizing agent in the sugar industry, which belongs to physical adsorption bleaching. From the perspective of whether bleaching is reversible, bleaching can also be divided into reversible bleaching (such as SO2, activated carbon) and irreversible bleaching (oxidative bleaching is irreversible bleaching).

Hydrogen peroxide is bleaching and relatively easy to oxidize.

Sodium peroxideIt is not bleaching per se.

Sodium peroxide itself is not bleaching, and the bleaching effect of sodium peroxide must be exerted in a certain medium, and this medium is generally water.

In general, sodium peroxide reacts with water to produce oxygen and sodium hydroxide.

This is only the phenomenon of the secondary limbs of sodium peroxide hydrolysis, in which it is the natural transfer of peroxide bonds, hydrogen peroxide.

The oxidizing essence of sodium peroxide is also that sodium peroxide is oxidizing.

Application areas of sodium peroxide:

Sodium peroxide can be used in medicine, printing and dyeing, bleaching and as an analytical reagent. It is used as an analytical reagent, such as an alkaline oxidizing solvent for decomposing samples.

It can also be used as an oxidant and preservative.

Deodorants, sanitizers, bleach.

Wait. It can also be used to prepare hydrogen peroxide. It is used to bleaching animal and plant fibers.

Feathers, animal bones, etc., are used as printing and dyeing agents for fabrics, carbon dioxide absorbers in the air, ventilation agents in submarines, chemical reagents, etc.

The above content reference: Encyclopedia - sodium peroxide.

Sodium peroxideThe bleaching principle is as follows:

When sodium peroxide reacts with water or dilute acid, hydrogen peroxide is formed.

And violently exothermic, the generated H2O2 is immediately separated and released from oxygen under the condition of heat, showing strong oxidation.

2Na2O2+2H2O=4NaOH+O2, therefore, Na2O2 is an important industrial bleaching agent.

Properties of sodium peroxide.

Sodium peroxide is one of the products of sodium combustion in oxygen or empty calendar careful gas, pure sodium peroxide is white, but the generally seen sodium peroxide is light yellow, because a small amount of sodium superoxide is generated during the reaction process (high school textbooks do not distinguish, Na2O2 is light yellow). Sodium oxide is easy to deliquescent and corrosive, so it should be sealed and preserved. Sodium peroxide has strong oxidizing properties and can be used to bleach textile products, straws, feathers, etc.

The above content reference: Encyclopedia - sodium peroxide.

Hydrogen peroxideWhen the waiter has the ability to bleach.

Hydrogen peroxide has strong oxidizing properties.

As long as it has strong oxidation, it has a certain bleaching ability, and this bleaching is still a permanent bleaching, which oxidizes the colored organic matter into a colorless, bleaching agent.

It is divided into oxidizing bleaching, binding bleaching and adsorptive bleaching, of which the combined bleaching is temporary bleaching.

Why is hydrogen peroxide bleaching:

Hydrogen peroxide (H2O2) is a strong oxidizing agent.

Hydrogen peroxide is a naturally occurring chemical substance found in air and water, and can be produced by light, lightning and microorganisms.

Hydrogen peroxide dissolves in water, and it becomes what people often call hydrogen peroxide old seepage.

In the food industry, hydrogen peroxide is mainly used for the sterilization of flexible packaging paper, the sterilization of canneries, milk and dairy products.

Sterilization, bread fermentation, decolorization of food fiber, etc., and is also used as a production and processing aid.

In addition, hydrogen peroxide plays an important role in drinking water treatment, textile bleaching, the paper industry, the medical industry, and the manufacture of household detergents.

The above content refers to Encyclopedia - Hydrogen Peroxide.

bleaching andOxidationThe difference:

1. The types involved are different.

The principle of strong oxidizing bleaching (permanent bleaching): the "chromophore" inside the organic chromophore is destroyed and oxidized into a colorless substance. Chemically bleached.

Principle: Addition or synthesis of colorless substances with colored organic compounds, and the color disappears after the decomposition of the colorless new substance. Principle of physical adsorption bleaching:

Absorbs organic pigments and fades. Common such substances are: activated carbon.

Colloid. <>

2. The law is different.

Bleaching regularity, sulfur dioxide.

It can fade many colored substances, but its fading principle is different: reducing fading: sulfur dioxide can make bromine water, acidic potassium permanganate.

The solution fades, taking advantage of the reducing properties of sulfur dioxide. Bleaching fades, acidic fades.

The law of oxidation: the law of reaction relationship, the oxidant gets electrons, valency.

reduced, reduced to a reduction product; and reducing agents.

Electrons are lost, and the valency increases and is oxidized to oxidation products. The law of knowledge clue relationship loses electrons, the valency increases, and the reducing agent. Common oxidants and their reduction products.

3. The definitions are different.

Bleaching can be said to be a manifestation of oxidation, which is the oxidation of colored substances into colorless substances. But oxidation is not necessarily bleaching.

First, the concept is different.

Oxidation refers to the ability of a substance to obtain electrons, and its strength mainly refers to the ease with which electrons are obtained. It should be pointed out that there is no necessary relationship between the strength of oxidation and the number of electrons gained and lost. That is, the oxidation is strong, and the number of electrons obtained is not necessarily large; On the contrary, if the number of electrons obtained is small, the oxidation is not necessarily weak.

Bleaching refers to the turning of natural or colored fibers and fabrics into white, and can also be understood as the fading of organic pigments under certain conditions. The fading of inorganic substances such as bromine water fading, chlorine water fading, and acid potassium permanganate fading do not belong to the bleaching range.

Second, the types involved are different.

The principle of strong oxidative bleaching (permanent bleaching): the internal "chromophore" of organic color quality is destroyed and oxidized into a colorless substance. Chemical bleaching.

Principle: Addition or chemical synthesis with colored organic matter to form a colorless substance, and the color disappears after the decomposition of the new colorless substance. The principle of physical adsorption bleaching: organic colors are absorbed and faded. Common such substances are: activated carbon, colloids. <>

Third, the law is different.

Bleaching law, sulfur dioxide can make many colored substances fade, but its fading principle is different: reducing fading: sulfur dioxide can make bromine water, acidic potassium permanganate, solution fade, using the reducing property of sulfur dioxide. Bleaching fades, acidic fades.

The law of oxidation: the law of reaction relationship, the oxidant gets electrons, the valency decreases, and it is reduced to a reduction product; The reducing agent loses electrons, and the valency is increased and oxidized to oxidation products. The law of knowledge clue relationship loses electrons, the valency increases, and the reducing agent.

Common oxidants and their reduction products.

The above content refers to Encyclopedia - Bleaching.

Encyclopedia - Oxidation.

First, the role is different:

Bleaching: The process of adding water and chemicals (oxidants or reducing agents) to remove the color contained in fiber materials, textiles, etc., and make them white.

Oxidation: Refers to the ability of a substance to gain electrons. Substances in the ** state and active non-metallic elements (such as fluorine, chlorine, oxygen, etc.) are generally oxidizing, while substances in the low-valence state are generally reducible.

Second, the meaning is different:

There must be a chemical change in oxidation, and there must be a change in valency. There are also chemical changes in bleaching, but not necessarily in valence.

Principle: Oxidation of colored substances into colorless substances.

Strong oxidizing bleaching agents such as: HCl, Ca(clo)2 (active ingredient of bleaching powder), Naclo, H2O2, Na2O2, O3.

HCOs: Strong oxidizing properties, often used for tap water disinfection (chlorine gas into the water).

Ca(clo)2: Ca(clo)2, CO2 and water produce HClo and are bleaching, which is often used for bleaching clothes and fabrics.

H2O2: H2O2 has strong oxidizing properties, and 3% hydrogen peroxide is commonly used in medical disinfection.

Na2O2: Na2O2 has strong oxidizing properties and is often used for bleaching fabrics, silk, wheat straw, etc.

The above content refers to Encyclopedia - Bleaching.