10 Most common acids and their uses

An acid is a substance with a pH of less than 7. They are characteristically sour or tart in taste and are typically classed into two main categories – strong acids (such as hydrochloric) and weak acids (such as acetic).

Acetic acid is a colourless, organic acid with a strong, pungent odour. A weak acid it is also referred to as ethanoic acid, methanecarboxylic acid and vinegar acid.

Uses of acetic acid

• Food and Drink:  Acetic acid is the main component of vinegar and is present in all types from weaker table vinegar through to pickling varieties. It is also found under the food additive number E260 as an acidity regulator and preservative.
• Cleaning Products: Given the acidic properties of acetic it makes for an excellent de-scaler and rust remover, often found in a range of household limescale removers.
• Adhesives and Paints: Vinyl acetate monomer is manufactured from a reaction consisting of ethylene, acetic acid and oxygen over a palladium catalyst that creates vinyl acetate. This can then be polymerised to a number of different polymers which are common components in adhesives and paints.
• Oil and gas: Acetic acid is also used in the oil and gas industry as an acidifying agent in the stimulation of oil wells.

Citric Acid, also known as Fruit Acid or 2-Hydroxypropane-1,2,3-Tricarboxylic Acid is a weak carboxylic acid and a naturally occurring fruit acid.  It is a white crystalline powder that is highly soluble in water and has a strong, acidic, and sour taste.

Citric Acid uses:

• Food and Drink: One of the biggest applications of citric acid is within the food and drink market where it is used as a flavour enhancer. It imparts a tart and sour taste, helps balance flavours and pH. It is also an excellent preservative which inhibits the growth of bacteria helping to increase shelf life and enhance appearance.
• Cleaning products and detergents: Citric acid is commonly found in many cleaning products and detergents where it acts as a binding agent to increase dirt and soil removal. It is also found in many everyday surface cleaners and scale removal products due to its low environmental impact and antibacterial properties.
• Reagent: Citric acid is used as a starting material in the synthesis of many other organic compounds and used as a reagent in various chemical processes including the production of detergents, dyes, and surfactants.
• Pharmaceuticals: In pharmaceuticals citric acid plays a key role due to the safe nature of the product. Its use produces effervescence for antacids and water-soluble tablets, masks bitter, medicinal flavours and offers excellent chelating and buffering properties.
• Personal Care products: Citric acid is a key ingredient in bath bombs where, when combined with sodium bicarbonate in water creates carbon dioxide for that fizzing action you see. It is also a component in many face creams where it works as an exfoliant and helps with softening skin and tone.

Formic acid, also known as methanoic acid, is a colourless, highly pungent weak organic acid. It is the simplest carboxylic acid and is an important intermediate in the chemical synthesis of many substances.

Uses of formic acid

• Animal Feed: Formic acid is used as an additive in animal feed and harvested silage. The addition of formic offers excellent antibacterial protection and supports fermentation at lower temperatures to preserve the nutritional value of the feed.
• Cleaning Products: Formic acid is a key ingredient in many everyday de-scalers and cleaners including kettle and coffee machine descalers and bathroom cleaners. Due to its low environmental impact, it is often used as an alternative to other traditional acids.
• Water treatment: Formic acid is a versatile and effective chemical used in water treatment to help maintain the quality and stability of water. It is commonly used to lower the pH of water to maintain the desired pH range for various industrial processes and to prevent corrosion in pipelines and boilers.
• De-Icing Products: Formic Acid has a low freezing point so when mixed with water it lowers the overall freezing point of the solution making it easier to melt ice and snow.
• Leather and textiles: The leather industry uses formic during the tanning process and for dye fixing. In other textiles, formic is used as a pH adjuster and to also help fabrics absorb more dye resulting in a more vibrant finish.

Hydrochloric Acid (HCl) is an inorganic, highly corrosive mineral acid. It is a clear, highly pungent solution of hydrogen chloride in water and classified as a strong acid.

Uses of Hydrochloric acid

• Cleaning products: Hydrochloric acid is found in many drain and toilet cleaners as well as mould removal products for its ability to dissolve mineral deposits. The corrosivity of this chemical effectively breaks down and removes a large number of very stubborn stains and build-up including hair, soaps, rust and scale.
• Swimming Pools: HCl in low concentrations is added to swimming pools to lower pH levels. If pool water is too alkaline it can reduce the overall disinfection effectiveness of chlorine. On the other hand, if pool water is too acidic it can cause skin and eye irritation and corrode equipment which is why testing for disinfectant levels and pH values needs to be carried out continuously whilst pools are in use.
• Leather processing: HCl is widely used (amongst other acids of choice) in the leather tanning process. Leather tanning is a procedure to preserve leather, enhance appearance and prevent it from decomposing. Using acids during this stage help to remove hair and organic materials from the hide, remove excess greases, adjust the pH and help prepare the fibres for other tanning agents.
• Reagent: HCl is an important reagent where it donates hydrogen ions to a mixture, creating an acidic substance. This then allows various chemical reactions to take place, including neutralising bases, dissolving certain substances, and breaking or forming bonds.
• Metal processing and refining: Hydrochloric acid is widely used in the steel industry as a pickling agent to remove oxide scale which forms on the surface of steel when it cools from a molten state. It is also used for etching, cleaning and in the recovery of metals.

Lactic acid is a clear to slightly yellowish, odourless, syrupy liquid. A weak, organic acid it has the chemical formula C3H6O3 and is also known under the food additive e number E270. 

Uses of lactic acid

• Food and Drink: Food grade lactic acid has a wide range of uses within the food and drink industry. It regulates pH, preserves fresh fruit and vegetables from discolouration, balances flavours and imparts a tart/tanginess to certain foods. In dairy products such as cheese, lactic acid controls the pH to increase shelf life and in brewing, lactic acid helps to reduce alkalinity to maintain optimum levels of pH throughout the brewing process.
• Cosmetics and personal care: Lactic acid is used as an exfoliant to remove dead skin cells and improve the appearance of skin. It is also a key ingredient in many cosmetic products such as cleansers, toners and moisturisers as it contributes to skin hydration and gives a more radiant appearance.
• Industrial: In industrial processes lactic acid is used as a pH adjuster, chelating agent and is the starting material in the production of polylactic acid (PLA).
• Cleaning Products: Lactic acid is environmentally favourable over traditional acids and possess excellent de-scaling and anti-bacterial properties. It is commonly found as the key ingredient in many drinks machine descaling products and antibacterial sprays.

Nitric acid is a highly corrosive, colourless mineral acid with a pungent odour. Also referred to as aqua fortis or spirit of niter it possesses the chemical formula HNO3 and is available in a wide range of concentrations depending on the end use. 

Uses of Nitric Acid

• Horticulture: Nitric acid is commonly used in crop irrigation systems (a system which delivers water around a growing area via drip, micro spray, or sprinkler). The addition of nitric lowers the pH of the water to inhibit limescale build-up caused by hard water. Alongside this nitric acid also serves as an excellent source of nitrogen for soil resulting in healthy plant growth and fuller crops. Nitric acid is also combined with ammonia to produce ammonium nitrate fertiliser. This product is used to acidify soil and promote healthy, fuller crops.
• Metal Treatment: Nitric acid is a common pickling agent chosen for its ability to remove impurities and oxidation from metal surfaces whilst not attacking the base metal.
• Textiles: Nitric acid is used in the textile industry as a bleaching agent where it helps remove impurities and yellowing from natural fibers such as cotton and wool. In addition to this, nitric is also used in the production process of certain dyes and in the finishing treatment of fabrics to lock in the colour.
• Explosives: Nitric acid plays a pivotal role in the manufacture of explosives. It is used in the production of nitro compounds such as nitrocellulose and nitroglycerin; the main components of dynamite.

Oxalic acid is an organic dicarboxylic acid with a white, crystalline appearance. It is soluble in water and also referred to as ethanedioic acid.

Uses of oxalic acid

• Wood Treatments: Oxalic acid is used as a bleach for removing stains and unwanted discolouration from wood.
• Metal Cleaning: Oxalic acid is used for the cleaning and restoration of metal surfaces where it easily removes rust and impurities from iron and steel.
• Leather and Textiles: Oxalic acid is used in the leather tanning process to neutralise alkalinity and increase the vibrancy of the leather. In other textiles it is used as a pH adjuster and to help remove mineral deposits from fabric.
• Agriculture: Oxalic acid is used as an insecticide as well as provide the plants with detoxifying function and assists in regulating various aspects of soil chemistry.
• Reagents: Oxalic acid is used as an analytical reagent in various chemical and biological tests.

Phosphoric acid is a weak, colourless and odourless inorganic acid. Also referred to a orthophosphoric acid it has the chemical formula H3PO4 and is known as a tribasic acid.

Uses of Phosphoric Acid

• Water Treatment: Phosphoric Acid has several uses in water treatment; To control pH, remove excess alkalinity, and remove dissolved metals such as iron, manganese and calcium.
• Food and drink: Phosphoric acid has multiple uses within the food and drink industry. It is added to balance or alter pH, sharpen taste, inhibit mould growth and stabilise the texture. It is also the starting point to numerous phosphate derivatives such as dicalcium phosphate, hexametaphosphate and sodium phosphate.
• Fertilisers: Phosphoric Acid is used to manufacture a range of different fertiliser end products such as DAP (Diammonium Phosphate), MAP (Monoammonium Phosphate) and TSP (Triple Superphosphate).
• Cleaning products and detergents: Phosphoric Acid is found in a wide variety of household cleaning products due to its ability to breakdown and remove soap residues, rust and mineral build-up.

Propionic acid is a colourless, organic compound with a strong pungent and sour odour. A carboxylic acid with the chemical formula C3H6O2, propionic acid is also referred to as propanoic acid, ethylformic acid or methylacetic acid.

Uses of propionic acid:

• Agriculture: Propionic has been used for many years for preserving grain and silage as a simple, effective, and cost-efficient method. Propionic acid quickly kills all forms of mould and yeast whilst maintaining the nutritional value of feed.
• Chemical Production: Propionic acid is used as a starting material in the production of other chemicals, such as propionates and acrylates.
• Cleaning products: Due to its antimicrobial ability, propionic acid is found in several cleaning agents specifically used for removing mould and mildew.
• Food and Drink: Propionic acid (Additive E280) is used in a range of processed foods to inhibit mould growth and increase shelf life.

Sulphuric acid is a clear, oily, viscous liquid comprised of hydrogen, sulphur and oxygen. It is a highly corrosive and strong inorganic acid with the chemical formula H2SO4.

Uses of Sulphuric Acid

• Agriculture and Horticulture: Fertilisers account for over half of the total consumption of sulphuric acid as it is a key raw material in the production of these products. Sulphuric acid is reacted with various other compounds to produce a wide range of phosphate fertilisers including ammonium phosphate and superphosphates. Sulphuric acid is also used a desiccant where it is sprayed onto crop before harvesting to kill vines, leaves, branches, and stems to help protect machinery and make crop harvesting easier. The low pH of this material also makes it ideal as a pH adjuster for very alkaline soils.
• Batteries: Battery grade Sulphuric acid is used in rechargeable lead-acid batteries where it serves as an electrolyte facilitating the conversion of stored energy into electrical energy.
• Petroleum refining: Sulphuric acid is used in the refining of crude oil to produce petrol, diesel, and other petroleum products.
• Cleaning products: Sulphuric Acid is a common ingredient in many drain cleaner products used to remove fats, oils, greases and organic build-up.
• Metal Processing and Treatments: Sulphuric acid is used within the iron and steel industry as a pickling agent to remove oxidation, scale and impurities from sheet metals.
• pH Adjuster: Sulphuric acid is widely used across a number of different industries as a pH adjuster for wastewater and effluent.

The 10 acids discussed in this article demonstrate the versatility and importance of acids in various applications. From serving as a key compound in cleaning agents to being used as a food preservative, acids play a key role in every aspect of our lives.

At Monarch we have a long history of distributing bulk packed acids to a wide variety of industries – from the UK agriculture sector to supplying a range of food grade acids to the food and beverage markets we work closely with all of our customers to ensure safe and timely delivery of all their acid products.

If you have a supply arrangement that is currently not meeting your purchasing objectives or are looking to increase your buying options for acid products please get in touch and we will be happy to help.