Bases, in general, are compounds that produce negative hydroxide ions when dissolved in water. They react with acids to form a salt. Bases include oxides, hydroxides, and carbonates of metals. Bases have a pH value of greater than 7. Some common examples where bases are used are soap, toothpaste, detergents, lime water, etc. In this article, we discuss the physical and chemical properties of bases.
Properties of bases
Physical properties of bases
- Bases are bitter to taste. (Warning: Do not taste any chemical).
- Aqueous base solution dissociates into ions to conduct electricity. For example, KOH dissociates into K+ and OH– ions in water.
- Bases are corrosive in nature depending on their pH and concentration. Handle all chemicals regardless of pH(acid or base) with care.
- Bases are mostly present in solid forms. But they do exist in solution and gaseous forms.
- Bases generally do not have an odor except for ammonia which has a pungent odor.
- Bases would turn red litmus paper blue
- Bases turn pink with the addition of phenolphthalein indicator
- Bases turn yellow with the addition of methyl orange
- Bases are identified by blue and violet color with universal indicator solution.
- Bases can be diluted with water to reduce the alkalinity of the solution.
Chemical properties of bases
- Bases have a pH greater than 7.
- Bases have the ability to accept protons from a proton donor.
- Bases react vigorously when dissolved in water. The reaction is exothermic.
- Bases react with acids to form salt and water. This neutralization reaction can be used for the synthesis of different types of salts.
- Bases like certain basic solid-zeolites have catalytic properties.
Theories of Bases
There are three different theories to define bases based on their properties. You can read more in our blog on the differences between acids and bases.
- Arrhenius theory of acids – States that a base produces hydroxide ions in aqueous solutions
- Bronsted-Lowey theory – It states a base as a proton acceptor
- Lewis Theory of acids – It describes bases as electron-pair donors
Real-life applications of the physical properties of bases
Bases like KOH(potassium hydroxide) are very well-known etching agents used to etch off metal surfaces to generate textures or specific shapes or patterns. KOH is widely used in the nanofabrication of silicon wafers used in the microchip industries. You can read more in detail here.
Alkaline electrolytes are widely used as electrolytes in electrochemical cells. You can read this research paper titled ” Synergistic Mn-Co catalyst outperforms Pt on high-rate oxygen reduction for alkaline polymer electrolyte fuel cells” where authors have used alkaline polymer electrolytes for their fuel cells.
Flower extracts like rose and hibiscus can also be used as natural acid-base indicator solutions. In this research article, the authors study three different flower extracts as possible acid-base indicators.
Real-life applications of the chemical properties of bases
Bases are used in the treatment of wastewater. The bases react with acidic compounds and neutralize them. They are also used as pH regulators to control the pH of untreated water. pH levels of water are very crucial for marine life and also for human consumption.
Bases like magnesium hydroxide are used in antacid formulations to treat acidity in our stomach. The antacid will react with the acids in our stomach and control the pH and give us temporary relief.
Bases are also used as catalysts for chemical reactions. You can read this research article titled “One-pot multicomponent synthesis of highly substituted pyridines using hydrotalcite as a solid base and reusable catalyst” where authors use a magnesium-aluminum hydrotalcite compound as a basic catalyst.
Bases are used to control chemical reactions. In this article titled “Effect of alkali bases on the synthesis of ZnO quantum dots,” you can see the effect of different bases on the synthesis of ZnO quantum dots. It affected the size, morphology, dispersity, etc of the final product.
