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VOOZH | about |
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VOOZH | about |
Base is a chemical compound that consists of OH- ions and accepts protons. Base in Chemistry are those compounds that turn red litmus blue and when reacted with acid they neutralize the reaction to give salt and water. The pH value of the base is greater than 7. Bases are bitter in taste and slippery in touch. The bases which are soluble in water are called Alkalis. Examples of Bases are Metal Oxides, Metal Hydroxides, etc. Soap is an example of a base that we use in daily life. In this article, we will learn about the definition, properties, and chemical reactions of Bases in detail.
Base is defined as the chemical compound whose pH value is greater than 7, accepts a proton, neutralizes acid, and turns red litmus to blue. They generally liberate OH- ion on dissociation. Examples include NaOH, NaHCO3, etc. Following are some general features shown by the base:
Bases are one of the most important chemical compounds that are used in everyday life. Bases are used as an antacid to control acidity and in toothpaste to neutralize the bacterial action that produces acid in our mouth and prevents degradation of enamel and cavity. They are also used as baking powder, baking soda, and washing powder.
Lewis Bases are the compounds that have electron pair and they can donate it to the compounds which are deficient in electron pairs. Lewis Bases are Nucleophilic in nature i.e., they are nuclei-loving which means they will attack a positively charged centre with their electron pairs. Examples of Lewis Base include Ammonia because in Ammonia (NH3) the centre atom Nitrogen has 5 electrons out of which 3 is used in making bonds with 3 Hydrogen atoms and one pair of electrons remains left with the N atom thus making NH3 a Lewis Base.
According to Arrhenius's Concept, Bases are compounds that release hydroxide ions when dissolved in water and increase the concentration of hydroxyl ions in the aqueous solution. For Example, when KOH is dissolved in water it will give OH- ion and thus increase the concentration of OH- in the water.
Bronsted Concept of Base is an advanced version of Arrhenius's Concept which states that bases are compounds that accept H+ ion or proton to form their conjugate acid. For Example Cl- is a base that accepts H+ to form HCl as its conjugate acid.
Bases can be classified on the basis of acidity, concentration, and ionization ability. The classification is mentioned below
Acidity of a Base refers to the number of replaceable hydroxyl groups present in one molecule of the base. Based on acidity, bases are classified into three categories:
Monoacidic: Mono-acidic bases are those that contain only one replaceable hydroxyl ion and interact with only one hydrogen ion. Monoacidic bases include NaOH, KOH, and others.
Diacidic: Diacidic base is a base with two replaceable hydroxyl ions that interact with two hydrogen ions. Ca(OH)2, Mg(OH)2, and other di-acidic bases are examples.
Triacidic: Triacidic base is a type of base that comprises three replaceable hydroxyl ions and three hydrogen ions. Triacidic bases include Al(OH)3, Fe(OH)3, and others.
Concentration refers to the amount of the base present in an aqueous solution. Based on their concentration in aqueous solution, bases are divided into two categories:
Concentrated Base: Concentrated bases are those in which the amount of base is large as compared to the solvent. Concentrated NaOH solution, for example.
Diluted Base: These types of bases have a lower concentration of base in their aqueous solution. Dilution is the process of reducing the percentage of a solute by adding more amount of solvent. For instance, dilute NaOH, dilute KOH, and so on.
Degree of ionization refers to the ability of a chemical compound to liberate their constituent ion when dissolved in water. In the case of Base, the degree of ionization refers to the ability of the base to release OH- ions when they are dissolved in water. Based on the degree of ionization, bases are classified into two types:
Strong Base: Strong Bases are those bases that dissociate completely and liberate OH- ion when dissolved in water. Some examples of Strong Bases include NaOH, KOH, etc.
Weak Base: The bases which don't undergo complete dissociation and liberate only a fraction of OH- ion is called Weak Base. Examples of Weak bases include Al(OH)3, Cu(OH)2, etc.
Learn More, Strong and Weak Bases
As we know that bases are chemical compounds that have OH- ion, turn red litmus blue, etc. In this section, we will learn about the physical and chemical properties of Bases along with some brief knowledge of their general properties.
The general properties of Bases are mentioned below:
Bases taste Bitter: Bases are bitter in taste. Due to its bitterness, we have only a few alkaline foods. There are only a few alkaline food materials. Bases need to be tasted with more caution as compared to acids.
Bases are Slippery in Touch: When touched Bases feel slippery. For Example soap.
Bases release OH- Ion: When bases are dissolved in water they release hydroxyl ion(OH-). Depending on the ability to liberate hydroxyl ions they are classified as Strong and Weak.
Bases neutralize Acids: When Bases react with acids, they neutralize each other and produce salt and water. This reaction is called Neutralization Reaction. Let's say we have the acid "HY" and the base ‘XOH,' then the salt formed will be ‘XY'. The equation for this reaction can be given as HY + XOH → HOH + XY.
Bases Denature Protein: Denaturation of Protein means the destruction of the stability and structure of the protein. This makes use of base harmful for humans as human skin and hair are made up of protein and when strong alkalis such as sodium or potassium hydroxide also called as Lye used they create a harmful impact on human skin.
Bases Turn Red Litmus to Blue: When bases are brought in contact with red litmus they turn it blue. However, it should be noted that no such change can be observed when we try to react dry base with red litmus paper. The Litmus Paper test is one of the oldest methods to test base. However, other indicators also exist such as Phenolphthalein
Bases Conduct Electricity: When bases are in solution form they have mobile OH- ion hence they can conduct electricity.
Alkali + Metal → Salt + Hydrogen
Examples:
- When sodium hydroxide interacts with aluminium metal, sodium aluminate and hydrogen gas are generated.
2 NaOH + 2 Al + 2 H2O → 2 NaAlO2 + 2 H2
- When sodium hydroxide interacts with zinc metal, it produces hydrogen gas and sodium zincate.
2 NaOH + Zn → Na2ZnO2 + H2
Non-metallic oxide + Base → Salt + Water
When Calcium Hydroxide, a base is reacted with Carbon Dioxide then Calcium Carbonate and Water is produced.
Ca(OH)2 + CO2 → CaCO3 + H2O
Alkali + Ammonium salt → Salt + Water + Ammonia
When calcium hydroxide reacts with ammonium chloride, calcium chloride water and ammonia are produced.
Ca(OH)2 + NH4Cl → CaCl2 + H2O + NH3
Bases generally are Metal Oxide, Metal Hydroxide, Metal Hydrogen Carbonate, Metal Carbonates etc. Let's see some of the examples of bases with their application in tabular form:
Bases | Applications |
|---|---|
Potassium Hydroxide KOH | Used in Alkaline Batteries |
Sodium Hydroxide NaOH | Used in the manufacturing of soap and detergent |
Magnesium Hydroxide Mg(OH)2 | Used as antacids |
Sodium Bicarbonate NaHCO3 | Used as Baking Soda |
Sodium Carbonate Na2CO3 | Used as Washing Soda |
Ammonia NH3 | Used in the manufacturing of Cleaning and Pharma Products |
Calcium Hydroxide Ca(OH)2 | Used in White Washing |
There are various use cases of base, some of these are:
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