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People have known about acids and bases for a long time. In 1680, Robert Boyle first described acids. He noted that they dissolve a wide variety of substances, alter the color of some natural dyes (such as litmus from blue to red), and then regain these properties when exposed to alkalis (bases). It releases the gaseous substance CO2 during acid-limestone reactions in the eighteenth century, and acids and alkalis interact to form neutral substances. Humphry Davy contributed to the modern acid-base idea by establishing that hydrogen is an essential component of acids. Also, Joseph Louis Gay-Lussac determined that acids are chemicals that neutralize bases and that we can only describe these two types of substances in terms of each other. He defined that acids dissolve in water to generate hydrogen cations, while bases dissolve in water to form hydroxide anions.
Common solutions include acids and bases. Except for water, almost all liquids have acidic and basic properties. They have distinct properties and can neutralize to form H2O, and physical and chemical properties define acids and bases.
Because ions dissolve in aqueous solutions, acid and base solutions can conduct electricity. So acids and bases are electrolytes. Strong acids and bases make strong electrolytes, while weak acids and bases make weak electrolytes, impacting conductivity.
About Robert Boyle
He was an Anglo-Irish chemist and natural philosopher born on January 25, 1627, in Lismore Castle, County Waterford, Ireland, and died in London on December 31, 1691. Richard Boyle, “Great Earl of Cork” (1566–1643), collaborated with Robert Hooke for more than a century after his father’s death on major studies on gas properties, particularly those expressed in Boyle’s law (see gas laws). In The Skeptical Chymist (1661), he criticized Aristotle’s understanding of the four elements (earth, air, fire, and water), supporting a corpuscular view of the matter that presaged modern chemical element theory. He was a famous scientist and Royal Society of London founder.
Robert Boyle’s notes
Properties of acids and bases
Acids corrode.
Acids have a sour taste.
Acids cause certain vegetable dyes, such as litmus, to change their color from blue to red.
Acids become alkaline when we combine them with alkalis.
The acid comes from the Latin word acidus, which means “sour.”
Because acetic acid is soluble in water, vinegar has a sour taste. Due to citric acid, lemon juice has a sour flavor and aroma because of the lactic acid that forms when milk spoils. We attribute rotten meat and butter’s sour odor to compounds like butyric acid.
Properties of Alkalis
Alkalis are slippery.
Litmus turns from red to blue when it comes into contact with alkalis.
With the combinations of acids, alkalis become less alkaline.
Boyle defines alkalis as acid-neutralizing chemicals. Acids lose their sourness and capacity to dissolve metals when mixed with alkalis. Alkalis even reverse the color change when litmus is in contact with an acid. Alkalis are bases because they form the “base” for certain salts.
Robert Boyle examples
A diluted acetic acid solution in water gives vinegar its sour taste.
Lemon juice is sour due to citric acid.
During milk spoilage, it forms lactic acid.
The sour smell of rancid butter comes from butyric acid formed when fat spoils.
Neutralization
The equations show that acids release H+ and bases release OH-. When we combine an acid and a base, the H+ ion combines with the OH- ion to make H2O:
H+(aq)+OH-(aq)→H2O
An acid neutralized by a base always produces water and salt, as shown below:
HCl+NaOH→H2O+NaCl
Although Arrhenius’ theories helped clarify the fundamentals of acid/base chemistry, they have limitations. Since baking soda (NaHCO3) does not contain hydroxide ions, the Arrhenius definition does not explain how it might behave as a base.
Danish scientist Johannes Brnsted and Englishman Thomas Lowry refined Arrhenius’ theory in 1923 by publishing independent but similar papers. “Bronsted-Lowry expanded the Arrhenius concept of acids and bases to include compounds capable of splitting or taking up hydrogen ions,” According to Bronsted.
The Arrhenius and Bronsted-Lowry definitions are similar: Acids can contribute hydrogen ions to another substance, and acids are proton givers because an H+ ion is simply a proton. However, the Bronsted definition of bases differs substantially from the Arrhenius definition. A basic, unlike an acid, may accept an ion of hydrogen. Because they can accept an H+ from acid and create water, NaOH and KOH are bases. The Bronsted-Lowry definition, on the other hand, explains why we can classify substances that do not contain OH- as bases. Here is an example of how (NaHCO3) can accept the hydrogen ion from an acid:
HCl+NaHCO3→H2CO3+NaCl
The carbonic acid (H2CO3) quickly decomposes to water and CO2, causing the solution to bubble.
pH
According to Bronsted-Lowry, acids and bases relate to hydrogen ion concentration. Acids increase hydrogen ion concentration, while bases decrease their concentration (by accepting them). The hydrogen ions concentration in a substance affects whether it is acid or base.
Sören Sörensen, a Danish biochemist, developed the pH scale in 1909 to measure acidity. The following formula defines the pH scale:
For example, a solution with [H+] = 1x 10-7 moles/liter has a pH of 7. pH varies from 0 to 14. We can classify from zero to seven substances as acids in the pH range of zero to seven. Since pH and [H+] are related inversely, lower pH indicates higher [H+]. Bases are substances with a pH above 7 and up to 14. Neutral substances, like pure water, are at pH = 7.
Conclusion
People have long known that lemon juice, vinegar, and many other foods are sour. Until recently, scientists discovered why these things taste sour: they’re all acids. In the seventeenth century, amateur Irish chemist and novelist Robert Boyle were the first to classify substances as acids or bases (which he called bases alkalis).
Acids corrode metals, taste sour, and make litmus red when mixed with bases. When combined with acids, bases become less basic and more slippery. It would take another 200 years for the first reasonable person to propose the definition of acids and bases, despite the efforts of Boyle and others to explain their behavior.
According to late 1800s Swedish scientist Svante Arrhenius, water may dissolve many substances by breaking them down into ion states. Acids, according to Arrhenius, are hydrogen-containing compounds that can dissolve in water and release hydrogen ions into the water solution.
