Determining Water Hardness and Alkalinity of a Natural Water Source
Introduction
Water hardness forms by presence of dissolved calcium or magnesium ions in water acquired through flowing in rocks. Limestone contains calcium carbonate while dolomite has both magnesium carbonate and calcium carbonate (FDACS, 2019). On the other hand, alkalinity is the process by which water has the capacity of resisting to changes in PH or the ability to neutralize the acid. Total alkalinity is created by carbonate and it is expressed in milligrams per liter (mg/L) or in parts per million (ppm). The common source of total alkalinity is calcium carbonate (Kegley and Andrews, 1998).
Water hardness originates from the dissolved ions of calcium and magnesium that are acquired as water flows through rocks. The compounds that contain the ions include calcium carbonate and magnesium carbonate (Extension.usu.edu, 2019). Total alkalinity originates from natural water that flow over rocks or ground that contains the carbonates compounds such as calcium carbonate and magnesium carbonate.
High alkalinity buffers the acid rain and acid which is important in protecting aquatic life. Hard water may be unsuitable for washing and alkalinity may be unsuitable for use in irrigation (Nollet and De Gelder, 2000).
The experiment is aimed at investigating the presence of alkalinity or hardness of water in a given sample provided. The process is critical in determining the quality of water and uses in both plants and animals. The process was investigated through titration and PH tests
Experimental Protocol
Week 1: Standard and natural water Hardness
The experiment was carried out through titration process. All the apparatus were assembled including burette and burette clamp. The titration process was between standardized 10 M M EDTA, 200 ppm CaCO3 and premade ammonium chloride-ammonia buffer solution. EBT indicator was used in the titration process. The solution of 10 M EDTA was titrated against CaCO3 until the end point where there was color change.
Week 3: Standard Alkalinity Titration
The experiment involved the titration of the CaCO3 solution with the H2SO4 solution of known concentration. The apparatus (burette, burette clamp) were assembled for the experiment. The next step involved filing the burette with 10ML of standardized 0.010 H2SO4 and titrated against the 50 mL of 500 ppm Na2CO3 solution. The indicator used in the experient was Bromocresol green solution. The PH electrodes were placed in the solution to monitor the PH change during the process. The results were obtained and recorded in a table and then a graph of PH against the volume of H2SO4 plotted.
Week 4: Water Alkalinity on Natural Water Sample
The water sample was used in estimating alkalinity. The value of the sample was (titrant) was estimated in the titration process with the acid. 40 ML of 0.002 H2SO4 was used in the titration and the volumes of PH and color recorded.
Results
Hach test strip= 25 ppm
8.5 mols CaCO3 yielded 17.0 ppm CaCO3
Concentration of CaCO3 = 17.0 ppm
Since the mole ratio is 1: 1, concentration of Ca2+= 17.0 ppm
Percentage = (17-12)/12×100=41.6 %
Volume of titrant H2SO4= 23.76 ml
Figure 1. Titration of 500 ppm Na2CO3 with 0.010M H2SO4
Concentration of Na2CO3= 330.5 PPM
Volume of titrant H2SO4 = 6.81 ml
Total alkalinity of water sample= 24.0 ppm
pKa = 10 for NaCO3
pKb= 14-10= 4
Average water sample concentration= 4 M
pKb= 14-4= 10
Discussion
The values are high relative to the average values or alkalinity or hardness of water. The references are not present owing that the procedure was conducted based on the samples provided. The hardness or alkalinity is appropriate for the natural sample because it falls within the acceptable range of alkalinity or hardness. The research might impact water companies to reduce important minerals for growth and health.
Conclusion
The experiment was conducted to investigate alkalinity and hardness in the water sample. The experiment was conducted for the purpose of investigating the effect of water hardness/alkalinity to people and animals. The result showed that the sample had an alkalinity of bKa 10.
References
FDACS. (2019). Aquarium Water Quality: Total Alkalinity and Hardness. Retrieved December 4, 2019, from https://www.fdacs.gov/Consumer-Resources/Recreation-and-Leisure/Aquarium-Fish/Aquarium-Water-Quality-Total-Alkalinity-and-Hardness.
Kegley, S. E., & Andrews, J. (1998). The chemistry of water. University science books.
Nollet, L. M., & De Gelder, L. S. (Eds.). (2000). Handbook of water analysis. CRC press.
Utah State University. (2019). Water Quality. Retrieved December 4, 2019, from https://extension.usu.edu/waterquality/learnaboutsurfacewater/propertiesofwater/alkalinity.
