The word acid always makes us think of something dangerous or harmful. But, we unknowingly use acids in our day-to-day lives. There are many uses of acids in our homes, industries, organic synthesis, and in our bodies. Here, in this article, we will discuss the general uses of acids and also the uses of 7 important acids: hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, carbonic acid, citric acid, and acetic acid.
Uses of acids in industries
- Acids like nitric acid, and sulfuric acid are used in fertilizer industries. (ex: phosphate and ammonium nitrate)
- Acids are used in the pickling process. They react with the metal to release hydrogen gas. This reaction is used to clean metal surfaces.
- Sulfuric acids and other acids are used as electrolytes in batteries.
- Carboxylic acids are widely used in the synthesis of esters.
Uses of Acids in our body
- Hydrochloric acid is one of the components of gastric juices in the stomach. It helps in breaking down complex molecules into simpler ones that are easier to absorb.
- Nucleic acids like RNA and DNA make up the genetic material in humans. Though DNA has both acid and basic parts in its structure,.
- Fatty acids are the basic units of fat in our bodies.
- Amino acids are the basic unit of proteins in our bodies. Not all amino acids are acidic. Only a few amino acids such as Aspartic acid, and glutamic acid are acidic in nature.
Uses of acids in food
- Citric acids are an important constituent of citric fruits. They are responsible for the sour taste of these fruits.
- Oxalic acids are present in tomatoes.
- Vitamin C(ascorbic acid) is present in most citric fruits and guava. It is an essential vitamin meaning our body cannot synthesize it.
- Carbon dioxide is made to dissolve in juices under high pressure to produce fizz drinks. This forms carbonic acid which is acidic in nature. The moment you open the drink the pressure is released and the carbon dioxide gas is released.
- Acetic acid is a major constituent of vinegar.
Uses of acids in catalysis
Strong acids like hydrochloric acid are used as acid catalysts for esterification reactions. The advantages of using acid catalysts over base catalysts are they don’t undergo saponification. Fischer–Speier esterification is an example of such a reaction.
- Brønsted acids are used for the conversion of fats into biodiesel. You can read this article for an example of the transesterification of fats into biodiesel.
- Metal crown ethers have been used as Lewis acid for aldol condensation reactions. You can read this article for examples of Lewis acid catalysts.
- Acidic groups supported on solid carriers like silica are widely used for solid-acid catalysis. You can read this research article titled” Silica-supported sulfonic acids as a recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols” for more details.
- Phosphotungstic acid (H3PW12O40) has been used for Friedländer condensation as a low-cost under solvent-free conditions. You can read this article for more information.
Uses of acids in pharmaceuticals/medicine
- Acetylsalicylic acid (Aspirin) is used as a pain killer and as a temporary relief for inflammation.
- Vitamin C(ascorbic acid) is used to treat patients with scurvy disease.
- Salicylic acid is used to treat dandruff, warts, ringworms, etc
Uses of Hydrochloric acid (HCl)
- HCl is present in our stomach as a constituent of gastric juice. It creates an acidic environment in the stomach to break down complex compounds into simpler molecules.
- HCl is used as a catalyst in many organic reactions.
- HCl is also used as a reagent in many acid-base neutralization reactions to produce inorganic salts.
- HCl is used for pickling metal surfaces especially in the pickling of steel to remove rust or any other contaminations.
Uses of sulfuric acid (H2SO4)
- Used in batteries as electrolytes
- Used in the synthesis of fertilizers, especially phosphate fertilizers.
- Used in the automotive industry as a cleaning agent to clean rust and other contamination from metal surfaces
- Used as a catalyst in many organic synthesis reactions, especially in petroleum refining.
Uses of hydrofluoric acid (HF)
- Used in the synthesis of fluorine-based organic compounds. A famous example of organic fluorides is CFCs(chlorofluorocarbon) used in refrigerators and air conditioners.
- Used as an acid catalyst in the petroleum industry
- Used as an etchant to clean the surfaces of silicon wafers in the semiconductor industry. These silicon wafers are then used to make all kinds of microchips. (Hydrofluoric acid is a very strong acid, and should not be handled with bare hands)
Uses of carbonic acid (H2CO3)
- Used in the manufacture of carbonated drinks
- Used for treating dermatitis
- Used in the food processing industries in form of its salts
- Used in cosmetics for skin brightening.
Uses of citric acid (C6H8O7)
- Used in the synthesis of buffer solutions
- It is used as a cross-linking agent for polymers
- Used to stabilize nanoparticle solutions as a capping agent
- Used as a chelating agent in hard water treatment
- Used in foods and beverages as a flavoring and preservative agent
Uses of nitric acid (HNO3)
- Used mainly in the synthesis of nitrogen-based fertilizers
- Used in the synthesis of explosives
- In organic synthesis, it is used as a reagent for the nitration of compounds
- Used in the synthesis of nitrate salts
- Used in the propellant mixture of rockets
Uses of acetic acid (CH3COOH)
- It is used in the manufacture of pesticides. It has a very bitter smell.
- Used in the synthesis of esters by reacting with alcohols
- Used as a starting material for the synthesis of cellulose acetate used for photographic films
- Used in our kitchens in the form of vinegar
- Used as a polar protic solvent in chemical reactions
What are the 5 practical everyday examples of uses of acids?
- Used in our kitchen in form of vinegar, citric fruit juices, tomato puree, etc.
- Mild acids are present in household cleaning agents.
- Used in electrolytes of the car battery.
- Used in the preparation of carbonated soft drinks.
- Gastric acid juice is for digesting food in our stomach.
