Base Meaning in Chemistry

Ionic compounds that dissolve in water and cause hydroxide ions to form are called bases. The term ionic compound refers to a compound containing both a negative non-metal ion and a positive metal ion linked by an ionic bond.

What is the Meaning of the Term Base?

In simple words, the base meaning is that it is the foundation of something that provides support to the thing which is built on it. But, the base meaning in chemistry is different. Base meaning in chemistry is that base is a chemical substance that is slippery to touch, tastes bitter, and changes the colour of indicators such as litmus paper. The base is a substance that reacts with acid.

Define Base, Chemistry

The word base has three different definitions in chemistry, and they are Arrhenius base, Bronsted base, and Lewis base. All the base definitions agree to the fact that bases react with acids.

Arrhenius Base 

Arrhenius base definition, chemistry defines base as a substance that gets dissociated in an aqueous solution to form hydroxide ions OH-. These hydroxide ions react with hydrogen ions to form water in an acid-base solution.

Bronsted Base

Bronsted base definition, chemistry defines base as a substance that can accept the hydrogen cations or protons. According to Bronsted, these substances that accept cations do not contain hydroxide ions, but they still react with water in order to increase the number of hydroxide ions.

Lewis Base

Lewis definition of base in chemistry defines base as a molecule with a high-energy pair of electrons that can donate a pair of nonbonding electrons to the acids that accept it and form an adduct. 

Properties of Bases

Here we have listed some general properties of basic substances or bases.

• Bases are slippery substances.

• Bases react with acid to form salt and water, the reaction of which is called a neutralization reaction.

• Bases are a good conductor of electricity.

• Bases tend to change the colour of litmus indicators, and they turn red litmus blue.

• Bases tend to lose their basicity when they are added to acid.

• Bases are bitter to taste.

• Some bases are used as electrolytes such as sodium hydroxide and potassium hydroxide.

• The pH value of bases ranges between 8-14.

• Bases do not react with metals as acids do. 

Examples of Bases

Here we have included 10 examples of base and their use in day-to-day activities.

Types of Bases

Bases can primarily be divided into two types: Strong bases and Weak bases. Here we will study in detail both the types of bases.

Strong Base

A strong base can be defined as a chemical compound that has the capacity to remove a proton from a molecule of even a very weak acid in an acid-base reaction. A strong base is that which has the ability to completely dissociate in an aqueous solution to yield one or more hydroxide ions per molecule of the base. A strong base reacts with strong acid to form stable compounds.

Here are some strong base examples.

• Lithium Hydroxide LiOH

• Sodium Hydroxide NaOH

• Potassium Hydroxide KOH

• Rubidium Hydroxide RbOH

• Magnesium Hydroxide Mg(OH)₂

• Barium Hydroxide  Ba(OH)₂

• Calcium Hydroxide Ca(OH)₂

• Strontium Hydroxide Sr(OH)₂

Weak Base

A weak base can be defined as a chemical compound that does not fully dissociate in an aqueous solution, or it can be said that the protonation in a weak base is always incomplete. When a weak base is added to an aqueous solution, it does not ionise entirely as a result of which the aqueous solution still contains a large number of undissociated molecules of the base. Now below, we will list some weak base examples. 

The following is a weak base example list.

• Alanine

• Ammonia

• Methylamine

• Ammonium Hydroxide  

What are ions? 

When electrons are lost or gained from atoms, they become charged particles. An example of a base is NaOH (sodium hydroxide). The compound generates negative hydroxide ions (OH-) and positive sodium ions (Na+) when it dissolves in water. A formula for the compound can be written as follows:

NaOH → H2O + OH− + Na+

Define Base, Chemistry

Arrhenius base, Bronsted base, and Lewis base are three of the different definitions of the word base in chemistry. It is generally accepted that bases react with acids.

Arrhenius Base 

In chemistry, Arrhenius bases are substances that get dissociated into hydroxide ions in aqueous solutions. An acid-base solution is formed by the reaction of hydroxide ions with hydrogen ions.

Bronsted Base

Bases can accept hydrogen cations or protons and are defined by Bronsted as substances. The substance accepts cations, but Bronsted argues that it reacts with water in order to produce hydroxide ions regardless of whether it contains hydroxide ions.

Lewis Base

Lewis defines a base as a molecule carrying a pair of highly energetic electrons that can accept a pair of nonbonding electrons from the acid molecule, forming an adduct with it. 

Types of Bases

• Strong Base – An acid that has very little proton can be eluted with the help of this compound. If the acid is dissolved in water, it completely dissociates into its ions. Some examples of these substances are potassium hydroxide (KOH) and sodium hydroxide (NaOH).

• Weak Base – The dissociation of the base in water is incomplete. As well as the weak base, the aqueous solution contains its conjugate acid. Ammonia (NH3), water (H2O), pyridine (C5H5N) are examples.

• Super Base – Deprotonation is more efficient when using these bases instead of a strong one. Their conjugate acids are very weak. Alkali metals and conjugate acids can be mixed to produce these compounds. Due to its stronger base than hydroxide ions, it can't sustain in aqueous solutions. Examples are sodium hydride (NaH), ortho-diethynyl benzene dianion (C6H4(C2)2)2−

• Neutral Base – A neutral base shares its electrons with a neutral acid.

• Solid Base – A solid base is active. An example of this is silicon dioxide mounted onto alumina.

The Properties of a Base

• Electrical current is conducted by ions in an aqueous base solution.

• The pH value is above 7.

• On reaction with acids, they produce salts.

• They promote certain chemical reactions.

• Alkaline solutions make them bitter.

• Concentrated or strong bases are caustic.

• Changing the indicator color from red to blue changes the color of the litmus paper.

• It can accept protons from proton donors.

• It contains OH− ions.

• Acids react vigorously with them.

• They are slippery to the touch.

• When dissolved in water, they conduct electricity.

Acids and bases have been defined and marked for the first time in the 17th century and have continued to be refined over time as we have improved our understanding of their chemical characteristics. Basic acid/base chemistry principles are introduced in this module, including neutralization reactions.