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Wednesday, January 25, 2023

Why pH Value is measured between 0 and 14?

The concentrations of the solutions in the lab are typically 1 M or less; therefore, we obtain no more than 1M hydrogen ions for pH 1, and for pH 14, we get no more than 1M hydroxide ions. The pH value, which ranges from 0 to 14, indicates the alkalinity and acidity of a solution.

pH is defined as the negative logarithm of the H+ ion (hydrogen ion) concentration. It is measured by the pH scale, which has a scale range of 0–14. A pH scale is used to measure acids and bases.

The mathematical definition of pH is simple; it states that pH is equal to the negative logarithm of the hydrogen ion (H+) concentration.
pH = -log [H+]
Solutions with a pH value between 0 and 7 on the pH scale are said to be acidic, and solutions with a pH value between 7 and 14 on the pH scale are said to be basic. Neutral solutions are those that have a pH of 7 on the pH scale.

The acidity or alkalinity of a solution can be measured by its pH using litmus paper (blue or red), pH paper, universal paper, indicator solutions, or more accurate electrochemical procedures employing electrodes and a pH meter (millivoltmeter).

Why does the pH range from 1 to 14?

Because the concentrations of the commonly used solutions in the pharmaceutical lab are normally 1 M or less, hence, we receive no more than 1M hydrogen ions for pH 1 and no more than 1M hydroxide ions for pH 14.

This is the most frequently asked question related to the pH scale by science/chemistry students in school/college. The pH scale doesn't range from 0 to 14. The pH values of common solutions fall within this range, although they may also be inside or outside this range.

This is supported by mathematical calculations employing equations that express the equilibrium constant and dissociation constant of the dissociation of water (H2O) into positive and negative hydrogen and hydroxide ions, respectively.

When the concentration of the solution exceeds 1M, the pH value leaves the range of 0 to 14. While in general, the pH value is the negative logarithm of the hydrogen ion concentration, chemistry graduates will know that technically, the value is a measure of hydrogen ion activity. Although this is difficult to estimate or detect experimentally, the former method is suitable for most cases with appreciable accuracy.

why is ph between 0 and 14

Summery:

  • The pH value of a solution is the negative base-10 log of the hydronium ion concentration of the solution.
  • We use solutions that typically have a concentration of 1 M or less. Therefore, at pH 1, we obtain only 1M hydrogen ions, while at pH 14, we obtain only 1M hydroxide ions.
  • Because pH is a logarithmic measure, a change in pH of one unit is equivalent to a ten-fold change in the concentration of hydrogen ions.


Commonly asked questions:

What does a pH level of 14 mean?
Any solution with a pH of 14 or higher is considered to be strongly alkaline.

Why does the pH level change?
If we add acid or base to the solution, the concentration of hydrogen ions increases or decreases, which causes a change in the pH level.

Why does pH change slowly at first?
Due to the logarithmic nature of the pH scale, meaning that a pH of 1 will have 10 times the hydronium ion concentration than a pH of 2, the pH rises slowly at first.

Why do pH papers contain only 1 to 14 no.?
Because it is a logarithmic scale, the pH scale ranges from 0 to 14 and is used to measure the acidity or alkalinity of a solution.


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Monday, January 23, 2023

Advantages and disadvantages of healthy food

Healthy food is essential for human health, appearance and energy. This can help us reduce their chances of developing health problems. Healthy food is more beneficial for our health than junk food or fast food. 

If people make the right food choices and follow their diet consistently, it can be easy to maintain. There are several healthy food options available, and we should determine what works best for us.

What is healthy food?

Foods that are high in nutrition and benefit our overall health are called healthy foods. It offers a variety of organic food options, including natural foods, whole foods, and no processed food. Any food that is high in vitamins, fiber, minerals, carbohydrates, fats, proteins, water, and other nutrients can be considered healthy. 

Some examples of healthy foods are nuts, vegetables, fruits, milk or dairy products, peanuts, pecans, and walnut, etc.

Advantages of healthy food:

  • The major advantage of eating healthy food is that it contains high amounts of vitamins and minerals, which are essential for the human body to stay energized and avoid health problems. 
  • It provides the body with more energy and essential nutrients that it needs to function optimally.
  • Healthy foods contain antioxidants that help eliminate potentially damaging cells (Free radicals)
  • Like junk food and fast food, eating healthy (homemade) food we does not get addictive tendencies.
  • A healthy diet can reduce the chances of chronic health problems.
  • It helps in achieving and maintaining a healthy weight.
  • Eating a healthy diet rich in vegetables, fruits, whole grains and lean meats is an excellent way to maintain a healthy heart in general.
  • It helps the body function better.
  • It helps in keeping the digestive system functional and healthy.
  • Healthy food can boost your immune system and a strong immune system helps in keeping a person healthy.
  • It helps to regulate the blood sugar level in the body.
  • Healthy food contains vitamins and minerals that can improve the health of your hair, skin, and nails.
  • It can support brain development and keeps your mental health.
  • By eating healthy food, we can reduce the risk of heart disease, type 2 diabetes and some cancers.
  • It contains calcium, which is an essential mineral to build and maintain strong bones and teeth.
  • It supports healthy growth, body muscles, healthy pregnancies and breastfeeding.
  • It can help you sleep better, have more energy, and live longer.

Disadvantages of healthy food:

  • The major disadvantage of eating healthy food is that it can be expensive and take longer to prepare than junk or fast food. It is not possible for a person with little money to buy fresh fruits and vegetables regularly. Maintaining a healthy diet can be difficult over time.
  • People have a wide variety of healthy food choices, but it can be challenging to identify the ones that work best for their diet.
  • Since it is difficult to carry healthy food from home to work and other places, we depend on restaurants, or hotels, or street food. Therefore we become accustomed to dining outside.
  • Adapting to the changes brought about by healthy eating in our way of life can be very challenging. Some food cravings can be the result of long-term habits that are difficult to break.
  • Organic and chemical-free foods are becoming increasingly scarce in the market.
  • Healthy food like junk food may not always suit your taste buds, and this is the reason why people get bored after a while.
  • Healthy food does not have the same attractiveness, taste, variety, palatability and availability as junk food or fast food by which children’s or people attracted.
Advantages and disadvantages of healthy food


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Thursday, January 19, 2023

Conditions required for diazotization titrations

Diazotization titration, also known as nitrate titration, is a type of titration used in the pharmaceutical analysis that involves the conversion of primary aromatic amines into specific diazonium compounds. Peter Griffin first discovered the reaction mechanism for diazotization titration in 1853.

As per the reaction the primary aromatic group reacts with sodium nitrite (NaNO2) and a diazonium compound or diazonium salt will be formed. To prevent azo coupling, the diazotization reaction is carried out in acidic conditions (HCl solution).

Basic conditions required for diazotization titrations:

The following are some basic requirements that must be met for the diazotization titration to proceed:

The temperature of the reaction:

An ideal temperature is required for all reactions to take place. This ideal temperature can be increased or decreased to significantly slow (Rate) or stop the process. Similarly, diazonium compounds are unstable at high temperatures and decompose easily. 

This may cause adverse reactions and give the wrong result. Therefore, to avoid this problem, titration needs to be performed at low temperatures (0 to 5°C). Most amines form relatively stable diazo compounds at temperatures between 10–150 °C.

Rate of titration:

The rate of reaction differs depending on the compounds. The rate of reaction of amino compounds with HONO will also vary. Depending on their rate of conversion, we can classify them as either fast diazotisable or slow diazotized. 

Compounds with sulpha groups, nitrous oxide groups, and carboxylic groups are known as slow diazotisable compounds. Fast diazotisable compounds are those that solely include amino groups, or -CH3 or hydroxyl groups.
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Diazotization Titration: Principle, Types, Applications

Learn the principle, theory, types, and applications of diazotization titration, which involves the conversion of an aromatic amine into diazonium compounds.

Titration is a method of chemical qualitative analysis used to determine the unknown concentration of an analyte. It is also known as titrimetry and volumetric analysis, in which an endpoint is determined by adding a known concentration of titrant to an unknown amount of analyte. Titration can be classified based on its procedures and goals, such as acid-base titration, precipitation titration, complexometric titration, and redox titration.

What is diazotization titration?

In pharmaceutical analysis, diazotization titration is a type of titration that involves the conversion of the primary aromatic amines into particular diazonium compounds. The reaction mechanism for diazotization titration was first discovered in 1853 by Peter Griessin.

According to his reactions, a diazonium compound or salt will be formed when the primary aromatic group reacts with sodium nitrite (NaNO2). Furthermore, the medium of this reaction is acidic.

Principle of diazotization titrations:

The basic principle behind diazotization titration is that, in the presence of an acid, the given sample of a primary aromatic amine will react with sodium nitrite (NaNO2) to yield a diazonium salt (for example, hydrochloric acid).

The chemical reaction of this process is as follows:

R-NH2+ NaNO2+ HCl→ R-N+≡ N-Cl–+ NaCl + H2O

Theory:

You will use sodium nitrite for the direct diazotization method in an acidic medium. it will release HNO2, and by measuring the volume of NaNO2 in the solution, we can easily analyze the number of primary amine groups that have free -NH2 groups.

The chemical reaction of this process is as follows:

NaNO2 + HCl →HONO + NaCl

ArNH2 + HONO + HCl →ArN2Cl + 2H2O

Using the starch paper test or an indicator, you can find the excess NaNO2 that is still present in the solution. Excess sodium nitrite (NaNO2) indicates that the reaction has reached its endpoint. The starch and I2 that are released at the end will react to produce a blue color. It is significant to note that it will only occur when an inorganic acid is present. Therefore, the following chemical reaction occurs to test it with starch iodide paper or solution:

KI + HCl →HI+ KCl

2HI +2HONO→ I2 +2NO +2H2O (excess)

I2 + Solution of paste of starch→ blue color (endpoint)

Types of diazotization titrations:

There are three different types of diazotization titration: direct method, indirect method, and other methods.

Direct Method:

The process consists of treating an amino group with an acidic solution, to yield the diazonium salts of the diazonium compounds. This solution will be stored in ice water to keep the temperature between 0 to 5°C. Then, titrate it with sodium nitrate and observe the endpoint.

Indirect method:

The indirect method of titration applies to insoluble diazonium salts. In this technique, you will need to add the excess nitrous acid into the sample titration solution. You need to titrate it against some other since it is an insoluble diazonium salt.

Other methods:

The other method consists of conversion into diazo oxides, which are typically more stable than diazo compounds.

Factors affecting diazotization titrations:

The following are some of the factors that affect diazotization titration:
  • The acid concentration used in titration
  • Time taken by the reaction
  • The efficiency of the attached diazotized group (rapid or slow)
  • The pH of sodium nitrite
  • Reaction temperature

Application of diazotization titrations:

  • The analysis of sulfonamides is the basic application of diazotization titration in pharmaceuticals.
  • It is used to determine the primary aromatic amine compound.
  • Diazotization titration is also used to determine the chlorophenol, alpha drug, procaine, etc.
  • It is commonly used in the dye and pigment industries.

Commonly asked questions on diazotization titrations are as follows.

What are the conditions required for diazotization titrations?
Maintaining the temperature of the reaction and rate of titration are the conditions required for diazotization titrations.

What indicator is used in diazotization titration?
Starch iodide paper is used as an indicator to indicate the endpoint of a reaction in diazotization titrations.

Why is HCl used in diazotization?
The diazotization reaction is conducted in the presence of excess HCl to avoid azo coupling.

What is the other name for diazotization titration?
Diazotization titration is also known as nitrite titration which is used in the analysis of aromatic compounds containing an amino group in the molecules.

What are the examples of slow and fast diazotized groups?
Nitrogen oxide, carboxylic groups, and sulpha, are examples of slow diazotized groups, and anilide, toluidine, and aminophenol are examples of fast diazotized groups.


Keaywords:
Applications, examples, principle, advantages and disadvantages
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Friday, January 13, 2023

Applications of redox titration

Titration is a common laboratory technique for quantitative chemical analysis, to determine the concentration of a specific analyte/solute by comparing it with the known concentration of a solution in the presence of an indicator. 

Titration is classified into four different types based on goals and processes such as acid-base titration, redox titration, precipitation titration, and complexometric titration.

What is redox titration?

Redox titration is an analytical method to determine the concentration of sample analyte, redox reactions are oxidation-reduction chemical reactions in which the oxidation states of the reactants change. In which a redox indicator solution or potentiometer is used to determine the endpoint.

There are different types of redox titration depending on the titrant used, such as permanganometry, iodometry, bromatometry, iodimetry, cerimetry, and dichrometry, and based on the method are direct titration and back titration.

The reactions involved in redox titration are redox reactions in which electrons are transferred and oxidation states are changed. As a result, redox titrations are a useful way to learn more about the substances we come into contact with.

Concept of oxidation and reduction:

Oxidation:
It could be described as the loss of electrons to an oxidizing agent to produce a more positive or higher oxidation state.

Reduction:
It could be described as gain electrons from a reducing agent to produce a more negative or lower oxidation state.

Applications of redox titration:

Redox titrations have numerous applications in chemistry, industrial analyses, food industries, pharmaceutical preparations, agriculture, environmental analysis, and other fields. Its common example is the titration of sulfite in wine using iodine, as well as that of alcohol, which can be determined based on its oxidation by potassium dichromate (K2Cr2O7).
  • Industrial applications of redox titration:
Evaluation of chlorination of public water sources is one of the most important industrial applications of redox titration. As well as to determine the purity or content analysis of raw materials, oxidation-reduction reactions are also used.
  • Pharmaceutical applications of redox titration:
Redox titration is used in pharmaceutical analysis to measure the concentration of active pharmaceutical ingredients (concentration of iron) in pharmaceutical goods, such as tablets, capsules, and other medicinal products.
  • Applications of redox titration in chemistry:
Redox reaction is most commonly used to identify elements with medium and high concentrations. Many inorganic analytes can be analyzed using redox titrimetry. In inorganic analysis, it is used to determine the water content in a non-aqueous solvent using Karl Fischer reagent as a titrant. As well as dissolved oxygen can be a determination by this method.
  • Applications of redox titration in food:
The food industry makes broad use of an analytical method that enables it to estimate how much of a reactant is present in a sample. Redox titration can be used to measure the concentration of salt, sugar content as well as vitamin C, and E content present in a food product.

Some of the real-life applications and common applications of redox reactions are as follows.
  • It is used to purify metals.
  • It is used in environmental analysis for the determination of dissolved oxygen.
  • Redox reactions are used to manufacture a wide variety of chemicals, including chlorine and caustic soda.
  • Redox Reaction is used in combustion
  • Redox Reaction is used in electrochemistry
  • Redox Reaction is used in photosynthesis applications
  • Redox Reaction is used in photographic Films
  • Redox reactions are used in the electroplating process
  • Oxidation-reduction reactions are used to sanitize water and bleach materials.

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Class 11 ncert pdf, medicine,  photosynthesis, pharmacy, potential, electrochemistry, everyday life, chemistry, dentistry, food, metallurgy, public health and environmental analyses.
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