Practical uses of buffer solutions

Buffer solutions as we have seen are extremely effective at minimising changes in pH, we have commented on their ability to stabalise pH at any range, depending on the pKa value and the concentrations of the acid and base used.
Buffer solution are used extensively throughout industry, forensics, pharmaceuticals and especially within physiological surroundings. In each case the pKa ranges of the buffer solutions are exactly tailored for their purpose.

Physiological buffers

Probably the most important use of a buffer solution is its application within our bodies. Without them to control the pH of solutions within our body we would not be able to function and would die. Buffer solutions provide the essential conditions for enzymes to function within our body. They also maintain the acidic pH levels required for digestion.

Within blood a buffer of Carbonic acid H2CO3 and bicarbonate HCO3- is used to maintain a pH between 7.35 and7.45: H2CO3 + H2O H3O+ + HCO3- HCO3- This buffer solution works in exactly the same way as the others we hav discussed in the website The acid is weak so the equilibrium lies to the left leaving plenty of undisociated acid molecules The extra bicarbonate present in the solution will push the equilibrium further to the left On the addition of extra H+ ions they will react with the bicarbonate ions present to form carbonic acid, as the equilibrium lies to the left the H+ ions will remain removed from solution. The acid molecules provide plenty of H3O+ions to react with any hydroxide ions present.

Pharmaceutical Buffers

• Shampoo
  Citric acid is added to shampoo as a 'pH buffer' Sodium hydroxide is also added as too keep the equilibrium to the left leaving plenty of citric acid molecules undisociated.
  The resulting buffer solution counteracts the alkylinity of the soaps and detergents present in the soap that would irritate the scalp.
• Baby lotion
  The buffered solution within baby lotion maintains a pH within the nappy of around 6, restricting the growth of bacteria within the nappy. This prevents nappy rash and keeps the baby happy!

Buffers in industry

Buffers are used extensively in the brewing industry to maintain the correct conditions for fermentation . Buffer solutions are added before fermentation begins to prevent the solutions becoming too acidic and spoiling the beer or spirits.

Buffer solutions are also used for setting the correct conditions for dying fabrics in the textile industry.