# Neutralisation in everyday life and industry

• Investigate applications of neutralisation reactions in everyday life and industrial processes

# Acid/Base use in industry

Acids and bases are used in multiple different industries including agriculture, chemical, food, pharmaceutical, and even everyday life

• Applications of acids and bases in the agricultural industry

• The pH levels of soil will affect the availability of nutrients for plants and thus plants are general quite pH sensitive and will be unable to grow if it is too acidic or too alkaline.

• If the soil is too acidic, we can add powdered lime or limestone which is basic and will neutralise the hydrogen ions which are present.

$$2H^+(aq) + CaCO_3(aq) \rightarrow Ca^{2+}(aq) + H_2O(l) + CO_2(g)$$

• If the soil is too basic, we can add compost and manure which will decompose to release organic acids, for example the rotting of leaves may release carbon dioxide gas which dissolves in water to form carbonic acid.

$$H_2O(l) + CO_2(g) \leftrightharpoons H_2CO_3(aq)$$

• Applications of acids and bases in the chemical industry

• Concentrated sulfuric acid is used as a dehydrating reagent in the synthesis of many organic compounds. H2SO4 is also an important catalyst in the production of esters (esterification). These formed esters are commonly used for their aromatic properties.

• Sulfuric acid is used to make phosphoric acid, which in turn is used to make phosphate fertilisers. Phosphate fertilisers produce a source of phosphorus which is essential for plant growth.

• The burning of fossil fuel releases large quantities of SO2 sulfur dioxide gas. Sulfur oxides form acid rain when mixed with the water in clouds. Similarly lime and limestone are used to neutralise the gases when they are released into the atmosphere

For spills, we use bases to neutralise acids, and acids to neutralise bases. Generally weak acids and bases such as sodium carbonate (Na2CO3) are used because the reaction between a strong acid and strong base is highly exothermic

• Applications of acids and bases in the food industry

• Artificial flavouring – citric acid (C6H8O7) is a triprotic weak acid that is naturally found in citric fruits, lemon and lime. However, it can also be artificially synthesised.

• Standard titration is performed to specify nutritional values.

• Carbonic acid (H2CO3) is used to make drinks ‘fizzy’. When a can of soft drink is opened and left in the open, the amount of H2CO3 in a carbonated drink decreases with time after it is opened because it breaks down into CO2 which leaves the system. At higher temperatures, this process occurs more favourably due to its endothermic nature.

• Preservation of food: acetic acid (ethanoic acid, CH3COOH) in vinegar. The acid kills the bacteria. This is achieved indirectly by inhibiting important biological processes and enzymes in bacterial cells

• Applications of acids and bases in the pharmaceutical industry

• Aspirin (IUPAC name: acetylsalicylic acid) is used to reduce inflammation by inhibiting biological enzymes and prevent clotting to reduce chance of stroke.

• Titration techniques are commonly used to ensure quality control throughout the production process of drugs.

• Antacid tablets are used to neutralise gastric acid in patients who experience heart burn and indigestion. We can infer this from the name which is representative of anti-acid

• Applications of acids and bases in everyday life

• Vinegar is a common remedy for wasp and jelly fish stings as their toxins are alkaline in nature. If we remember vinegar contains the common weak acid acetic acid.

• baking powder contains sodium hydrogen carbonate. When water is added to the baking soda, carbon dioxide is released to help rise cakes and doughs, giving them their signature airy texture

• Toothpastes are alkaline are help to prevent the acidic decaying food particles in our teeth. They can contain varying compositions.