An acid is a solution that gives away hydrogen ions in the solutions like hydrochloric acid. Similarly, a solution that gives hydroxide ions is called base or alkali. The acidic and basic nature of a solution can be ascertained with the help of its pH level. The pH level is a negative logarithm of the concentration of the hydrogen ions in the solution. So, where the concentration of hydrogen ions is determined in a solution, you can determine its pH level. You can change the concentration of the solution by adding acid or base to the solution. If you add more of the former, it increases the concentration of hydrogen and decrease the pH level. On the contrary, adding hydroxide ions can decreases the concentration of hydrogen and increase the pH level of the solution. So, the question arises, if you can make such solutions where pH remains constant even after adding a little acid or base? Certainly, you can! These solutions can be made with no change in pH even after you add acid or base to the solution. They never show any change in the pH and such solutions are referred to as buffer solution. Please see this website to know more.
Types of Buffer Solution
It is inevitable that you only need a small amount of strong acid to change the pH of a solution. A strong solution with high acidic or basic nature can completely ionize and weak acid or alkali cannot. And some un-disassociate molecules will always remain in the solution. These molecules will affect the equilibrium in the dissociated ions. Many reactions are needed to address to the constant pH to gain the desired results. And for the same, we need buffer solutions. They are referred to the solutions where pH is constant no matter how much of an acidic or basic solution you add. The constant pH is due to the reaction of extra hydrogen or hydroxide ions where some of them cannot be ionized further. There are two types of buffer solutions: acidic and alkaline buffer solutions. The former has the pH level below 7 and is obtained by adding weak acid and salt like a mixture of acetic acid and sodium acetate. The latter has a pH level above 7 and is obtained by mixing ammonium hydroxide with ammonium chloride.
Some examples of Buffer solution in nature
You can find many buffer solution examples in the nature. In the living organisms, a carbonate buffer is indulged in order to maintain the pH of blood which is affected by the process of respiration. Respiration gives away carbon dioxide which is acidic in nature where the blood is a weak basic solution. The dissolution of CO2 in water tends to form carbonic acid which is weak in nature in order to maintain the pH level of the solution.
Factors that affect the pH level of buffer solution
- Ionic strength of solution
When adding neutral salts to the buffer solution, the pH level is affected. As the ionic strength of the salt changes, the ionization keeps the activity of constant, activity of ionized species of the buffer constant, and activity of hydronium ion tends to be affected which further affects the pH of buffer solution.
The acid, ionization constant, and the base dissociation constant of water changes with temperature.