Determination Of Alkalinity Of Water By Titration Pdf
Alkalinity is a crucial parameter that determines the quality of water. It is defined as the ability of water to neutralize acid. Alkalinity is essential to maintain the pH balance of water and prevent the water from becoming too acidic. The determination of alkalinity of water by titration is a widely used method to measure the alkalinity of water. In this article, we will discuss the process of determining the alkalinity of water by titration and its significance.
What is Alkalinity of Water?
The alkalinity of water refers to the capacity of water to neutralize acid. It is measured by titration with a strong acid to a specific pH endpoint. Alkalinity in water is primarily due to the presence of dissolved bicarbonate, carbonate, and hydroxide ions. Alkalinity is essential because it acts as a buffer against changes in pH caused by acid addition. If the alkalinity of water is low, then the water can become acidic quickly.
Why is it Important to Determine Alkalinity of Water?
The determination of alkalinity of water is crucial because it can affect the operations of various water treatment processes such as disinfection and coagulation. Alkalinity is also essential for the survival of aquatic life. A low alkalinity level can result in the growth of harmful algae and negatively impact the aquatic ecosystem.
Determination of Alkalinity of Water by Titration
Titration is the process of determining the concentration of a substance in a solution by adding a known volume of that solution to a solution with a known concentration. The determination of alkalinity of water by titration involves adding a known volume of an acid (usually sulfuric acid) of known concentration to a water sample until a specific endpoint pH is reached. The endpoint pH is usually between 4.2 and 4.5.
The alkalinity of the water sample can be calculated using the following formula:
Alkalinity (mg/L as CaCO3) = (Acid Volume x Normality of Acid x 50,000)/Sample Volume
In this formula, the acid volume is the volume of acid added to the water sample, the normality of the acid is the concentration of the acid, and the sample volume is the volume of the water sample.
The Procedure for Determining Alkalinity of Water by Titration
The procedure for determining alkalinity of water by titration involves the following steps:
- Fill a burette with an accurate volume of sulfuric acid solution of known concentration.
- Measure a representative sample of the water to be tested (usually 100mL) into a conical flask.
- Add a few drops of the indicator to the water sample. The commonly used indicators are phenolphthalein and methyl orange.
- Titrating the water sample by slowly adding sulfuric acid from the burette while stirring the water sample until the endpoint pH is reached. The endpoint pH can be determined by the color change of the indicator. If phenolphthalein is used, the endpoint pH is reached when the color of the water changes from pink to colorless. If methyl orange is used, the endpoint pH is reached when the color of the water changes from yellow to orange.
- Record the volume of the acid added to the water sample.
- Calculate the alkalinity of the water sample using the formula discussed earlier.
Conclusion
The determination of alkalinity of water by titration is a widely used method to measure the alkalinity of water. Alkalinity is a critical parameter that affects water quality and the survival of aquatic life. The knowledge of alkalinity of water is essential for efficient water treatment processes. The procedure for determining alkalinity of water by titration is simple and straightforward, and it can be carried out in a laboratory setting or in the field. By following the procedure, we can ensure the safe and efficient use of water resources.
