The calibration of pH meter was performed resulting a calibration equation Y=-57.833+403 (see appendix). After the calibration of pH meter the pH values show in the table 3, 6, 7, 10, 11 and 13 were calculated from the values of mv recorded by using aforementioned equation. Despite the values the pH reading were recorded the values used and reported in this experiment were the calculated pH.
The standardization of the titrant solution HCL was performed fallowed a potentiometric titration, described in (w), which allowed us calculate the true concentration from four different methods. The sodium bicarbonate with a concentration equal 0.01 mol/L, this value is considered be of high precision and accuracy since …show more content…
The endpoints of the pH indicator method were observed at 33.6 mL, 38.8 mL and 44.6 mL respectively. In the visual identification the endpoints were found at 33.8 mL, 39.2 ml and 44. 6 mL these value can be observed in the figures 5, 8, and 11. In the numerical differentiation method the endpoints found were 33.6 mL, 39 mL and 44.6 mL. From The final method, Grant function, the endpoints were 33.4 mL, 38.4 mL and 44.6 respectively the values can be observed in the 7, 10, and 13. The endpoints for all method were reached at pH range 4.2-4.6. The endpoints found allow determine the equivalent of alkalinity at which the alkalinity concentration for the first, second and third replicate of the sample were calculated.
From the table 5 and 6 the average alkalinity of sample resulting for the first trial was 0.002003 mol/L (73.01 mg/l). For the second trial the result is 0.001936 moles/L (63.52 mg/L) and for the third method the value resulting was 0.001958047 moles/L (71.39 mg/L) respectively. All results of alkalinity are express as Calcium Carbonate CaCO3. The minimum values found is 56. 95 mg/L and the maximum value obtained is 76. 25 mg /L According to these results alkalinity meet the standard of aquatic life criteria of the EPA (7) which establishes as criterion continuous concentration a minimum value …show more content…
The Information concerning alkalinity of a water give us an valuable information that is used in the practice since this parameter is widely useful in various aspects of environmental engineering. The alkalinity results can be used in chemical coagulation, water softening, corrosion control, buffer capacity control and industrial waste. Alkalinity has little public health significance. Highly alkaline water usually unpalatable and consumer tend to seek other supplies (8). The four methods performed afford us determine success the alkalinity of a natural water. According to the results obtained, the alkalinity values, from all methods are high accuracy. The values found in this experiment are within the range of common value found in natural water in the New York (3) as well the found alkalinity results meet the standard value established for aquatic life according to the published table of