Alkalinity of Water Questions and Answers for Viva

Answer-1: It is due to the presence of hydroxide, carbonate and bicarbonate ions.

Answer-2: Sure, the steps typically involve:
1. Preparing a water sample of known volume.
2. Adding a few drops of a pH indicator (methyl orange) to the sample, causing it to turn pink.
3. Titrating the sample with a standard solution of sulfuric acid (H₂SO₄) while stirring.
4. Continuously monitoring the color change until the solution turns from pink to orange.
5. Recording the volume of acid required to reach the endpoint.
6. Calculating the alkalinity based on the volume of acid used and the concentration of the acid.

Answer-3: Alkalinity measurements can be used to assess the water's ability to resist pH changes and, by extension, its ecological health. In natural water bodies, alkalinity helps maintain stable pH levels, which is crucial for aquatic life. It can also provide insights into the presence of carbonate and bicarbonate ions, which are important for buffering against acid rain and pollution.

Answer-4: There are several methods to determine the alkalinity of water, with the most common ones being titration methods. These include the Gran method and the pH titration method. Other methods include the methyl orange method and the pH colorimetric method.

Answer-5: Colourless in acid and pink in alkaline.

Answer-6: Total alkalinity is determined by using methyl orange.

Answer-7: Alkalinity is a measure of the water's capacity to neutralize acids or its ability to resist a decrease in pH. It is essential to measure alkalinity in water because it helps assess the water's buffering capacity, which is crucial for maintaining stable pH levels in natural water bodies. Monitoring alkalinity is important in environmental science, as it provides insights into the water's ability to resist changes in acidity due to pollution or natural processes.

Answer-8: The Gran titration method is based on the principle of titrating the water sample with a strong acid (usually sulfuric acid, H₂SO₄) to a specific endpoint, indicated by a color change due to the addition of a pH indicator (usually methyl orange). The amount of acid required to reach this endpoint is proportional to the water's alkalinity.

Answer-9: Several factors can affect the accuracy of alkalinity measurements, including:
The choice and quality of the pH indicator used.
Contamination of glassware or the sample.
Incomplete mixing during titration.
Incorrect calibration of equipment.
Presence of interfering substances in the water sample.

Answer-10: Hydroxide ion and half of carbonate ion.

Answer-11: The endpoint in the Gran titration method is the pH at which the solution changes from pink to orange. The pink color indicates the presence of hydroxide ions (OH^-) due to the water's alkalinity. The endpoint is determined by monitoring the color change using a pH indicator like methyl orange. The endpoint is reached when the pink color disappears, and the solution turns orange.