1. Definition of Acid and Bases:
1.1 Arrhenius definition of acid and base:
Arrhenius Acid:
The substance or a compound which gives H+ ions in aqueous solution
Arrhenius base:
Base is a substance or compound that produces OH- ions in aqueous solutions.
Chemists have known for some time that the H+ ion doesn’t exist in aqueous solutions as an independent species. The modernized Arrhenius definition of acid is that they are substances that produce H3O+ ions in aqueous solutions. It did not take longer for chemist to find other problems with the Arrhenius definition. In practical terms, the OH- ion is far from being the only base.
1.2 Bronsted-Lowry definition:
Bronsted-Lowery definitions acid and a base, consider the net ionic equation for any Arrhenius acid-base reaction in water:
H3O+ + OH- 2H2O
When it reacts, the H3O+ ion gives up a proton, passing it to the OH- ion. This means that H3O+ is a Bronsted-Lowry acid in this reaction. The OH- in turn accepts the proton, making it a Bronsted-Lowry base.
The advantages of the Bronsted-Lowry definitions are that they cover acids and bases other than H3O+ and OH- .Consider:
HSO4- + PO43- SO4- + HPO42-
During this reaction the HSO4- ion donates a proton and is therefore an acid. The reaction ion turns the HSO4- ion into the SO4- ion. The PO43- ion becomes the HPO4- ion during the same reaction. That is, the PO43- ion accepts a proton, which means that it is acting as a base.
1.2.1 Bronsted-Lowery Acid-Base Reactions:
Conjugate Acids and Bases:
Conjugate Acid:
When a proton (not a hydrogen atom or “hydrogen” but a proton, H+) is added to a molecule or ion, its conjugate acid forms.
Exampl...
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...near to neutral if not that particular drug or medicine may cause irritation in body tissues.
• Fermentation process requires a specific pH for the best results. The pH during a fermentation process changes by itself due to fermentation process so buffer play important role in controlling this pH change.
• Buffers are also used in foods to maintain the acidity of the food in order to preserve the flavour and appearance of food.
• Dyes in textile industries play an important role in giving colour to different fabrics. Colour strength of dyes is closely associated to narrow pH range which is maintained by using different buffer systems. pH above or below this narrow range will affect the colour imparting ability of different dyes.
• In Leather industries narrow range of pH control of tanning and dyeing baths determine the texture and colour of the finished product.
As shown in equation 2, the reaction between the phosphonium salt and the sodium hydroxide produces the ylide/carbanion that is stabilized due to the positive charge on phosphorus and the conjugation that occurs in the benzene ring as shown by the structure B in equation 2. The ylide produced also has a resonance form (B’). The resonance form is advantageous because it contains no formal charge and the double bond it contains results in the same position of the double bond in the final a...
CL-, as the ions of H+ and OH- react to form H2O. These spectator ions
If more than one complex is formed at different pH values, their existence can be decided by this type of study. The pH, at which the absorption due to a particular complex species is far greater than that of metal ion and or the ligand alone, is selected for the study of that species. As the complex formation is the function of pH; it should be kept constant for particular system. Similarly, ionic strength is maintained constant throughout by adding an appropriate volume of sodium perchlorate. pH can be remained constant by using suitable buffer, provided the buffer does not interfere with the complex formation at wavelength where complex species show maximum
Most substances fall on a scale ranging from the most acidic to the the most basic with neutral substances falling somewhere in the middle. Scientists call this the pH scale. pH levels are measured in numbers,0 to 14. The closer a substance is to zero the more acidic it would be. The closer to 14 the more basic a substance would be.Now what defines an acid and a base, one might ask? There are three ways of defining acids, each singling out a specific property. The first theory is the Arrhenius Theory with states, that an acid is a substance that produces the ion H+ when in a water solution, while a base is a substance which produces the ion OH- when in a water solution. Examples of an Arrhenius acid are HCl and HNO3. Examples of an Arrhenius base are NaOH and AlOH3.
Oxalic acid dihydrate is a diprotic acid acid and can therefore give away 2 protons (hydrogen ions). It is a reducing agent. Oxalic acid dihydrate is a primary standard acid which is a solid acid and whose mass is an accurate measure of the number of moles of H+ ions it will furnish and is therefore used in the titration with
Apply a leather preparer to eliminate the finish of the leather. This will allow the dye to be properly absorbed by the leather.
strong acid or base does not necessarily yield a drastic jump in pH. The acid
In Chemistry 221, we are learning how to name acids. In this lab we used hydrochloric acid (HCl), the reason I knew it was called “hydrochloric” was due to the rules of naming acids. When there is no oxygen involved, the “hydro” prefix is put in front, followed by the root of the second element (which happened to be chlorine) and then add the suffix –ic at the end.
Alcohol, which is the nucleophile, attacks the acid, H2SO4, which is the catalyst, forming oxonium. However, the oxonium leaves due to the positive charge on oxygen, which makes it unstable. A stable secondary carbocation is formed. The electrons from the conjugate base attack the proton, henceforth, forming an alkene. Through this attack, the regeneration of the catalyst is formed with the product, 4-methylcyclohexene, before it oxidizes with KMnO4. In simpler terms, protonation of oxygen and the elimination of H+ with formation of alkene occurs.
To maintain H+ in the body fluids, the input of hydrogen ions must be balanced by an equal output. On the input side only a small amount of acid capable of dissociating release H+ is taken in with food. Most hydrogen ions in the body fluids are generated internally from metabolic activities. The major source of H+ is through H2CO3 formation metabolically produced CO2. Cellular oxidation of nutrients yields energy with CO2 and H2O as end products. Catalysed by the enzyme carbonic anhydrase, CO2 and H2O from H2CO3 which then partially dissociates to liberate free hydrogen ions and HCO3-. The reaction is reversible because it can go in either direction, depending on the concentration of the substances
s) (aq) (aq) (g) Magnesium will react with hydrochloric acid, because it is higher in. the reactivity series of hydrogen. When the two chemicals react a displacement reaction will take place and the magnesium will displace. the hydrogen in the hydrochloric acid forming magnesium chloride and hydrogen gas. Reactivity Series K (potassium)
Cl- (aq) + Na+ (aq) + OH- (aq) Na+ (aq) + Cl- (aq) +H+ + OH- [IMAGE]The above is an example of a neutralization reaction, involving an acid and an alkali. The result is a salt and water. In every neutralization reaction, the metal in the alkali (Na+ here) takes the place oh the hydrogen in the acid, forming a metal compound called a salt.
Acid-Base Titration I. Abstract The purpose of the laboratory experiment was to determine equivalence. points, pKa, and pKb points for a strong acid, HCl, titrated with a. strong base, NaOH using a drop by drop approach in order to determine. completely accurate data. The data for this laboratory experiment is as follows.
With the expansion of technology available to the textile industry emerged a growing want among those who produced the textiles for new colors. When this problem arose, textile producers called upon the chemistry industry to help lessen the need for textile producers to rely upon natural methods of bleaching such as sun, rain, sour milk, and urine (Britannica). While these methods had been practiced for centuries, the industry saw a definite want for a new and more efficient method of bleaching. From this point forth, chemistry’s role in the Industrial Revolution not only led to innovations in bleaching, but also led to great changes in the practice of chemistry, as we know it. In the mid-1700’s, a chemist named John Roebuck solved the problems of the textile industry with his invention of a new method for mass producing a chemical by-product known as sulfuric acid in lead chambers (Encarta 97). This discovery paved the way for sulfuric acid’s use in bleaching, and eventually led to the production of chlorine bleach, a common household product today.
This gives up a proton and is thus an acid (hence amino "acid") [IMAGE] One of 20 different "R" groups. It is the structure of the R group that determines which of the 20 it is and its special properties. The amino acid shown here is Alkaline. Amino acids contain an amino or NH2 group and a carboxyl (acid) or COOH group.