Why caustic soda?
Why caustic soda?

Why caustic soda?

Why caustic soda? Sodium hydroxide as a highly reactive alkali is widely used in various industries.

Caustic soda has a faster and stronger reactivity than other alkali materials.

This material does not produce adverse effects such as carbon dioxide or other carbonates during chemical processes.

Caustic soda can be used for pulp and paper industry, aluminum production,

Ink-removing waste paper, water purification and disinfectants.

Caustic soda is the primary substance in the production of many chemicals.

This substance is used as an intermediate and reactive process in which
many materials are made up of solvents, plastics, synthetic fibers,
bleaching agents, adhesives, coatings, inks, paints,
herbicides and pharmaceuticals such as aspirin.

Caustic soda is also used for the soap and construction of detergents, oil and gas industries,

The ceramic industry is used to neutralize acidic wastewater and to clean and
remove acidic compounds from exhaust gases.

so, this chemical is one of the most used chemicals in the industry.

Usages of sodium hydroxide

Chemical production:

In the chemical industry, about 40% of the produced caustic soda is used as a
base material for the production of many chemicals.

Detergent and disinfectant products:

Caustic soda is used for the production of soap and detergents with various
household and industrial applications.
Chlorine bleaching solutions (bleaching agents containing chlorine such as sodium
hypochlorite) are obtained from the combination of chlorine and caustic soda.
Tubes that contain caustic soda,
By converting fats and oil materials that have the potential for blockage of pipes
and water and sewage routes,
Water soluble materials prevent blockage of the pipes.

Medical and Pharmaceutical:

Caustic soda in the production of many pharmaceutical and medical substances
from simple painkillers, such as aspirin, to anticoagulants that can prevent blood coagulation and
It is used in steroidal anti-arrhythmic drugs.

pulp and paper production:

Sulfate and sulfite pulp produced by purification of lignin compounds using
multiple units extracted by liquid caustic soda are purified.
Also, in some factories that use the craft process to produce paper,
Liquid sodium hydroxide is used.
In addition to the usages of caustic soda, in the paper industry,
this chemical isThe Initial removal of ink from recycled paper.

cellophane and silk:

The production of fibers using the viscose process requires two main steps needs caustic soda.
Cellulose is used to enhance the strength and shine, resulting in the production
of alkaline cellulose by the liquor of treated liquid,
The resulting cellulose is then dissolved in the diluted liquid extract to produce
viscose material used to extrude silk fibers and cellophane films.

Aluminum extraction:

The use of caustic soda in the aluminum industry is used to dissolve bauxite ore,
which is the primary material for the production of aluminum,
and the deposition of aluminum?
Caustic soda is also used for chemical brushes of aluminum products.

Soap making:

The caustic soda converts fats into water-soluble soaps.
the cloth:
In this industry, caustic soda is used to clean, whiten and enhance the shine
and toughness of the cloth.

Oil production and refining industry:

Caustic Soda as a carbon dioxide absorber in lightweight cuts
As sulfide adsorbent, it is used to purify various oil cuts.
Also, caustic soda along with chlorine for the hypochlorite
sweetening process that is a process for
The removal of various sulfur compounds is applicable.

Sodium carbonate substitute (soda ash):

Caustic soda is used as an alternative to its hydrate in many applications in the glass
paper, pulp, phosphate and silicate industries.

Food Production:

Sodium hydroxide is used in the production and processing of several nutrients.
Such as the use of caustic soda in the processing of olive or in the process of producing woody salty to create brittle.
The fruit is used to separate the peel of potatoes, tomatoes and other fruits for canning.
Also, caustic soda is used to prevent the growth of bacteria and mildew in certain foods and to prevent their corrosion.

Water and Sewage Treatment:

In water and wastewater treatment plants, water utilization is used to control
the acidity of water and help remove heavy metals from water.
Also, the caustic soda is in the production of sodium hypochlorite (bleach),
which is an antiseptic.


The use of caustic soda is used in the production of fuel cells.
In the manufacture of epoxy resins, which are used in wind turbines,
Caustic soda is used.

Nonrenewable fuels:

Caustic soda is used to adjust the pH and produce sodium methyl’s in the
bio-ethanol and biodiesel production process.

Chemical pollutants
Chemical pollutants

Chemical pollutants

Chemical pollutants are divided into organic and mineral groups.
Organic compounds contain carbon and hydrogen. Some organic particles are found in the atmosphere more than other organic particles,
These include phenols, organic acids, and alcohols.
The most famous minerals in the atmosphere are nitrates, sulfates, and metals such as iron, lead, zinc, and vanadium.

Sources of pollutants

The air has natural pollutants such as fungal spores, plant seeds, particles of salt and smoke, and particles of dust from forest floods and eruptions of volcanoes.
Also, the air contains carbon monoxide gas produced naturally (CO) from the decomposition of methane (CH4) and hydrocarbons in the form of tropanes from pine trees, hydrogen sulfide (H2S) and methane (CH4) from the anaerobic degradation of organic matter.

The sources of pollutants, in general, can be classified into four main categories:

Includes motor vehicles, air vehicles, trains, ships and any kind of use or evaporation of gasoline,
Including the supply of energy and heat for residential, commercial and industrial purposes, power generating plants that operate with steam,
Such as the chemical industry, metallurgy, paper production, and oil refineries,
Includes residues from domestic and commercial use, coal waste and ash remaining from the burning of agricultural remains.


Organic compounds that only contain hydrogen and carbon are called hydrocarbons, which are generally divided into two groups.
• Aliphatic hydrocarbons
The aliphatic hydrocarbon group includes alkanes, alkenes, and alkanes.
The alkanes are saturated hydrocarbons that are not involved in atmospheric photochemical reactions.
The alkenes commonly referred to as olefins,
Are not saturated and somewhat active in photochemical in the atmosphere.
This group reacts at high concentrations in the presence of sunlight with nitrogen oxides
And secondary pollutants such as proxy acetyl nitrate (PAN) and ozone (O3).
The aliphatic hydrocarbons produced up to about 326 mg / m3 for human and animal health are not risky.

aromatic hydrocarbons

Aromatic hydrocarbons biochemically and biologically active, some of them potentially carcinogenic,
Either derived from benzene or related to it.
An increase in the incidence of lung cancer in urban areas has been attributed to multi-nuclear hydrocarbons exhausted from cars.
Benzo pyrin is the worst cancer of hydrocarbons.

Sources of hydrocarbons

Drive shaft and carburetors have the highest percentage of hydrocarbon release.
Complementary combustion equipment that works with the catalyst releases hydrocarbons and burns carbon monoxide and generates CO2 and water.
Hydrocarbon control technology derived from residential resources
Hydrocarbon control technology derived from residential sources include gravel, adsorption, condensation, and alternative materials.
The graveling process is carried out with supplementary combustion devices and catalytic burners.

Carbon monoxide

The carbon monoxide gas is odorless and colorless, tasteless and under normal conditions, it is chemically ineffective and has an average lifespan of about 2.5 months in the atmosphere.
At present, the amount of carbon monoxide in the atmosphere is ineffective or less effective on human assets, plants, and objects.
In high concentrations of carbon monoxide, due to its high tendency to absorb hemoglobin, it can seriously disrupt human respiratory metabolism.
The concentration of carbon monoxide in densely populated urban areas where heavy traffic and vehicle movement are slow,
Significantly increases.
Carbon sources are natural and human carbon monoxide.

Carbon monoxide control standards

When the amount of carbon monoxide in a short time reaches deadly levels and becomes an emergency,
To cope with such conditions, when the amount of CO reaches an average of 46 mg / m3 (40ppm) over a period of 8 hours,
Extreme control operations are performed which include:
Stopping industrial factories and blocking roads where there is usually a heavy traffic.
Absorption, adsorption, condensation, and combustion are the technical methods for controlling CO.

Sulfur oxides

These oxides include six different gas combinations:
Sulfur monoxide (SO), sulfur dioxide (SO2), sulfur trioxide (SO) sulfur tetraoxide (SO4), sulfur dioxide
Sulfur oxide (SO2) and sulfur heptoxides (S2O7). In the study of air pollution,
Sulfur dioxide and sulfur trioxide are most important.
Due to the relative stability of SO2 in the atmosphere, this can act as an oxidizing or reducing agent.
SO2, which reacts with other components present in the atmosphere in the form of a photochemical or catalytic process,
It can produce sulfuric acid droplets (H2SO4) and sulfuric acid salts.
SO2 reacts with water, producing sulfuric acid.
This weak acid is associated with more than 80% SO2 released into the atmosphere from human activities to burn solid and fossil fuels.

Sulfur oxide control standards

Extensive methods for controlling sulfur oxide include:
The use of fewer sulfur fuels, the separation of sulfur from fuel, the replacement of other energy sources,
Conversion of coal into liquid or gas, cleaning of combustion products.

Nitrogen oxides

It contains nitrogen monoxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O).
nitrogen cis-oxide (N2O3), are Nitrogen tetroxide (N2O4) and Nitrogen Pentoxide (N2O5).
Two important gases in the air pollution equations are:
Nitric acid (NO) and nitrogen dioxide, nitrogen dioxide, which is heavier than air and soluble in water.
In water, it forms nitric acid or nitric acid or nitric oxide (NO).
Nitric acid and nitro acid have fallen to the surface as a result of rainfall,
Or with ammonia in the atmosphere (NH3), which combines ammonium nitrate (NH4NO3).
In this case, NO2 is a component of plant nutrition.
NO2, which is a good absorbent energy in the ultraviolet radiation range,
In the production of secondary pollutants such as ozone, O3 plays an important role. The amount of NO released in the atmosphere is far more than NO2 released.
NO is produced in high-temperature combustion processes due to the combination of nitrogen and oxygen.

Nitrogen oxide sources

Some nitrogen oxides are naturally occurring and some form humans.
A small amount of NO2 comes from forest fires. Bacterial decomposition of organic matter also liberates NO2 in the atmosphere.
In fact, NO2-producing resources are approximately ten times as tight as human resources in urban areas of concentration and concentration.
The major part of NO2 generated from human resources is the combustion of fuel in residential and transport vehicles.

Nitrogen oxide control standards

Often control measurements for NO2 are released in order to limit combustion conditions and reduce NO2 production as well as the use of diverse equipment to remove NO2 from exhaust gases.

Photochemical oxidants

Oxidizers or full oxidizers are two phrases used to describe photochemical oxidizing agents and
Usually, they indicate the ability to oxidize the air in the atmosphere.
Ozone (O3), a major photochemical oxidizer, accounts for about 90% of oxidizing agents.
Other important photochemical oxidants in air pollution control are:
Neonatal oxygen (O), Excited molecular oxygen (O2), Proxy acyl nitrate (PAN), Proxy propanol nitrate (PPN)
Proxy butyl nitrate (PBN), nitrous oxide (NO2), hydrogen peroxide (H2O2) and alkyl nitrate.
The effects of oxidizing agents
The effects of oxidants on human health can cause coughing, shortness of breath, airway obstruction, chest pain,
Inappropriate lung function, red blood cell changes, dry swelling, and burning eyes, nose and throat.

Acid Properties
Acid Properties

Acid Properties

Acid Properties: A sharp water or acid (in Latin acids means sour) is a chemical substance.

The characteristics of its aqueous solutions include sour taste, the ability to change the color of the blue to red,

And also the ability to react with bases and some special metals (such as calcium) and salt formation.

 aqueous solutions have a pH less than 7.

The bottom pH means more acidity and a higher concentration of hydrogen ions.

Solutions or chemicals that have the same acidic properties are acidic.

Acid is said to be hydrogen-containing substances that can react with metals and produce hydrogen gas.

General Properties of Acids

  • The ingredients with the sour taste.
  • Their aqueous solution release proton ions.
  • Paint the litmus paper red.
  • Combined with some metals such as iron and zinc, and liberates hydrogen gas.
  • Reacts with alkalis (alkalis) and forms salts.
  • They react with calcium carbonate, for example, in the form of marble, so that they float and release carbon dioxide

Arrhenius’s theory of acids

When the chemical ionization concepts were clarified in aqueous solutions,

The concept of acid has changed considerably.

According to Arrhenius, acid is a is material that ionized in water, and it produces ion + H3O, which is sometimes shown as + H.

(HCl -> H + + Cl- (aq

Arnius also interpreted acidic power on this basis, saying that strong acid is almost completely ionized in aqueous solutions.

If the amount of acid dissolution is lower.

Notice that the Arrhenius concept is based on water ions.

By the definition of Arrhenius, the role of acid oxides can also be interpreted

Acid oxides

Many oxides of non-metals react with water and produce acid,

As a result, these substances are called acid oxides or acidic acid.

N2O5 (s) + H2O → H + + NO3-aq

The Bronsted-Lowry acid-base theory

By definition, Bronsted – Lowry, the acid is a substance that gives a proton to alkali.

Acids may be molecules or ions.

By removing the proton, the acid is converted to the alkali (alkali acid 1), and by acquiring the proton, the initial opening, the open 2, becomes acid 2 (the conjugate acid 2).

Acid 2 + open 1 <- acid 1 + open 2

The strength of acids is based on their desire to lose or absorb proton.

The stronger the acid, the weaker the alkali conjugate it is.

In one reaction, the balance in the formation of acid is weaker. Perchloric acid, HClO4, is the strongest acid, and its alkali conjugate, ion perchlorate, -ClO4, is the weakest alkali, and H2, the weakest acid and its conjugate, ion-hydride, + H, is the strongest open.

Louis’s theory of acids

According to Louis, acid is a substance that can form a covalent bond by accepting an open electron pair.

In Louis’s theory, the concept of the electron pair and the formation of covalent bonding are emphasized.

Luis’s definition of things is much broader than what he has said. Chemical compounds that can play the role of acid Louis include:

  • Molecules or atoms that have incomplete octaves.

(BH3 + F- → BH4- (aq

Many simple cations can play the role of acid Louis.

Cu + 2 + 4NH3 → Cu (NH3) 4 + 2

  • Some metal atoms form acid in the formation of compounds such as carbonyls produced by the reaction of metal with carbon monoxide:

Ni + 4CO → Ni (CO) 4

  • Compounds whose central atoms have a tiny expansion of their thickness,

In the reactions that this expansion extends to, they have an acid role,

For example, in the opposite reaction, the thickness of the central atom (Sn) extends from 8 to 2 electrons.

SnCl4 + 2Cl → SnCl6-2aq

Some compounds have acidic properties due to the presence of one or more double bonds in the molecule.

For example, CO2

Acidic Power and Molecular Structure

In order to investigate the relationship between molecular structure and acidity,

The acids are divided into two types:

Covalent hydrides and oxyacid.


Some hybrid covalent binary compounds (such as HCl, H2) are acidic.

Two factors affect the acidity of the hydride element:

Elemental electronegativity and elemental atomic size

. The acidity of the hydrides of the elements of a period increases from left to right, in line with the electronegativity of the elements.

An electronegative element takes up more electrons from hydrogen and accelerates its release as a proton.

The acidity of the hydrides of the elements of a group increases by increasing the size of the central atom.

In the second alternation: NH3> H2O> HF in group VI is as follows:

H2Te> H2Se> H2S> H2O


In these compounds, acidic hydrogen is attached to an O atom, and the change in the size of this atom is negligible.

Therefore, the key factor in the acidic power of these oxides is the electronegativity of the atom Z: H-O-Z.

If Z is a non-metallic atom with high electronegativity, it contributes to the reduction of the electron density around the O atom (in spite of intense oxygen electronegativity).

This phenomenon causes the oxygen atom to accelerate its separation by making the electron density of the H-O bond of the H atom, and make the composition acidic.

Hypocaloric acid, HOCl, is an acid of this type.

The greater the electronegativity of Z, the H-O bond electrons are far more atomic H, and it is easier to remove the proton: HOCl> HOBr> HOI.

In oxygen oxides where more oxygen atoms are attached to Z, acidity increases with increasing n

The most important strong acids

The molecules of these acids are completely ionized in dilute aqueous solutions.

Conventional acids are: chloride, iodide, nitric, sulfuric, per chloric acid.

The most important weak acids

Ionization of these acids is not complete in water and never reaches 100%.

The conventional examples are acetic acid, carbonic acid, fluoride acid, nitric acid and, to some extent, phosphoric acid.

Some uses of acids

sulfuric acid

One of the most powerful mineral acids with the formula H2SO4 is a light and dark oil.

An industrial utility that is used extensively in oil refining and in fertilizer, paint, pigments, dyes, and explosives.

acetic acid

An organic acid is a colorless liquid with the formula CH3COOH, which is also the basis for vinegar.

The major part of the world’s most acid-free, alcohol-based reaction is used to produce esters that are used as the best solvents in paint and polish.

Also, in pharmaceutical factories, the practice of natural rubber and the supply of artificial leather and as a solvent for many organic compounds of acetic acid is used.

nitric acid

A strong mineral acid with the formula HNO3, which is used by the user in nitrate fertilizers and ammonium phosphate fertilizers, nitro blast, plastics, dyes, and varnishes.

Sulfonic acid

These acids, with the general formula HSO3R, where R can be methane or benzene, etc.,

Soluble in water, non-volatile and absorbent, and as emulsifying agents,

Lubricants and lubricants are used to prevent corrosion and rust.

Hydrochloric acid

One of the strongest mineral acids with the formula H Cl, which is a pale yellow or slightly yellowish, is very corrosive and non-flammable.

The acid is dissolved in water, alcohol, benzene and used in the acidification (activation) of oil wells, waste boilers sedimentation, food industry, cleaning of metals, and so on.