Acids and bases are fundamental chemicals in chemistry. In organic chemistry, the carboxylic acids have acidic properties, but in inorganic chemistry there is a wide range of acids with a variety of properties.
Definition of Acids and Bases
The word acid comes from the Latin word, which means sour or sharp to the taste, and liquids like vinegar and lemon juice are well-known acids. Other properties of acids are that they are corrosive to some metals and turn a material called litmus, which is an indicator extracted from moss, red.
Any hydrogen-containing material capable of transferring a proton (hydrogen ion) to another substance is defined as an acid. A base is a molecule or ion that can receive an acid’s hydrogen ion.
Some common acids are citric acid – found in fruit juice, ethanoic acid – found in vinegar, sulfuric acid – found in car batteries, and carbonic acid, which is also known as soda water.
There are other chemicals that, when added to a mixture of acid and litmus, will turn it blue. These chemicals are called bases (alkalis when they are soluble) and their reaction with acid is called neutralisation.
Common bases are calcium hydroxide (lime), sodium hydrogencarbonate (baking soda), magnesium hydroxide (milk of magnesia), and ammonia.
What is the primary distinction between an acid and a base?
Acids and bases are two types of corrosive chemicals. Any item with a pH between 0 and 7 is considered acidic, whereas anything with a pH between 7 and 14 is considered basic. Bases, on the other hand, are ionic substances that, when dissolved in water, form hydroxide ions (OH-).
How can you tell the difference between acids and bases?
Count the hydrogens on each component before and after the reaction to determine if it is an acid or a basic. If the number has reduced, the substance (which gives hydrogen ions) is the acid. If the quantity of hydrogens in a material has grown, that substance is the base (accepts hydrogen ions)
Acidity Depends on Hydrogen Ions
The behaviour of acids and bases is related to the presence of hydrogen ions (H+) in the solution. When an acid dissolves in water, it releases hydrogen ions, which cause the acidic properties.
A strong acid, like sulfuric or hydrochloric acid, is an acid which is completely ionised in solution (Important: it has nothing to do with the concentration of the solution). A weak acid, like ethanoic or citric acid, is an acid that is not completely ionized.
The activity of a base is explained by its reaction to hydrogen ions. So, a base is able to react with hydrogen ions, reducing the acidic nature of the solution. Some bases are metal hydroxides, and the hydroxide part reacts with the hydrogen ion to make water.
Other bases are carbonates or hydrogen carbonates which react with the hydrogen ions to make carbon dioxide and water. This explanation of how acids and bases work is called the Brønsted-Lowry definition of acids and bases, after the two scientists who first proposed it in 1923.
The pH Scale
A scale to demonstrate how acidic or basic a solution is has been developed, called the pH scale. It ranges from 1 to 14, in which the lowest numbers are for the most acidic and the higher numbers are the most alkaline, with pH 7 being neutral. The formula to work out the pH value is:
pH = -log [H+]
where [H+] is the concentration of hydrogen ions in the solution.
Some examples of pH values:
- pH1: stomach acid
- pH3: vinegar
- pH5: rainwater
- pH7: pure water
- pH9: baking soda
- pH12: mineral lime
- pH14:s odium hydroxide (Caustic Soda)
The Basic Chemistry
When a material is introduced to water, it creates hydrogen (H+) ions. A hydrogen ion is made up of only one proton and no electron. Looking at the formulations of several acids, we can observe that they all have at least one H (hydrogen), for example:
- Hydrochloric acid (HCl)
- Sulfuric acid (H2SO4)
- Nitric acid (HNO3)
- Acids are naturally corrosive.
- They are excellent electrical conductors.
- Their pH levels are always lower than 7.
- These chemicals create hydrogen gas when they react with metals.
- Acids have a sour flavor.
- Sulfuric acid [H2SO4], hydrochloric acid [HCl], and acetic acid [CH3COOH] are a few examples.
Some qualities, like as bitterness, are shared by all bases. The bases are also slick. Bases conduct electricity when submerged in water because they are made up of charged particles in the solution.
- When they are touched, they have a soapy feel.
- When these chemicals are dissolved in water, they emit hydroxide ions (OH– ions).
- Bases are strong conductors of electricity in their aqueous solutions.
- Bases have pH values that are always greater than 7.
- Bases are bitter-tasting chemicals that may turn red litmus paper blue.
- Sodium hydroxide [NaOH], milk of magnesia [Mg(OH)2], and calcium hydroxide [Ca(OH)2] are a few examples.