Why Is it Important to Know the Alkalinity & Acidity of the Solution?

Alkalinity

• A solution's alkalinity is a measurement indicating its ability to react with a strong acid to a predetermined pH. It is measured based on its carbonate, bicarbonate and hydroxide content. Alkalinity affects a variety of chemical reactions and biological processes, such as nitrification. The higher a solution's alkalinity, the greater the amount of neutralizing agent that must be added to a solution in order to counteract it. This information is of extreme importance in wastewater treatment facilities to ensure that treated water is safe for use.

Acidity

• The corresponding property of a solution's alkalinity is its acidity, which is the solution's ability to react with a strong base. The acidity comprises a solution's total acidic composition, including its percentage of both strong and weak acids as well as salts. The pH value of a solution may not be an accurate reflection of its acidity, as a sample with a neutral pH may actually be highly acidic. Acidity indicates the corrosive properties of a solution, which is critical for any scientist to know when transporting a solution or mixing it with other chemicals.

Preparing Samples for Analysis

• Chemistry students and professionals alike assess the acidity and alkalinity of a solution in the same manner. A sample should be gathered using a medicine dropper and placed in a glass test tube or bottle. The container should be filled to brim so there is no headspace for gas dissolution. A tight seal on the glass tube or bottle is important while it is stored at 4 degrees Celsius for two weeks, in accordance with Environmental Protection Agency guidelines.

Titration Analysis

• Each sample's acidity and alkalinity is easy to determine without advanced machinery or complex equipment. Titration is a simple analysis technique with which all secondary science students should be familiar. After storing a solution according to EPA instructions, place the sample in a beaker on a ring stand and pipet sulfuric acid into the beaker until the solution reaches a pH of 4.5. The amount of acid needed to titrate the sample indicates the solution's alkalinity. Repeat the experiment on a clean sample, titrating the solution with sodium hydroxide to a pH of 8.3.