Determination of Chlorides
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ISE: The Determination of Chloride
Unknown: #34
Purpose:
In experiment V, “ISE: The Determination of Chloride”, the concentration of an Unknown Chloride solution, and the Wt% of NaCl in a sample of celery salt, were both determined. To determine the concentration of an Unknown Chloride solution, a Calibration plot is first prepared.
The Calibration plot is made by first measuring a series of known concentrations of Cl- (with the same activity of the unknown solution) and obtaining a set of E-values for these standards -A graph is then plotted from the corresponding E-values vs. the logarithm of the concentration of Cl-. Once all the data points have been plotted, the slope of the line is determined (found by using a least squares calculation) -which is then used (the slope) to find the concentration of the unknown from the measured E-value of the unknown chloride solution. In the determination of the Wt% of NaCl in a sample of celery salt, the method of standard additions was used to find the Wt% of NaCl in our celery sample.
Experimental Parameters:
Theoretical Equations
Standard Additions Method
Sample Calculations
Concentration of Chloride in the Calibration Solution
Calculation of Slope, Intercept and Equation of for the Calibration Line
LLS Table
Calculations
Theoreical Electrode Slope & Relative Error of Measured Electrode
Concentration of the Cl- Unknown
Wt% Cl- in Unknown
Y-Axis Variable for the Standard Additions Plot, Value of Vs’
Concentration of Chloride in Celery Sample (ppm & M )
Calculation of the Wt% NaCl in Solid Celery Salt
Data and Results
Calibration Data
Calibration Graph
See Attached Graph Calibration Plot.
Calibration DataTable
Data Points for Calibration Plot.
Log [Cl-]
E (mV)
-1.2142
-1.3579
-1.552
-1.7874
-2.0511
-2.2574
-2.7184
-3.0167
-3.4115
-3.7117
-3.9332
-4.1671
-4.41
-4.7109
Standard Additions Data
Standard Additions Graph
See Attached Graph Standard Additions Plot
Standard Additions Data Table
Data points for the Standard Additions Plots
Vol (mL) KCl Added
Potential (mV)
Y-Values
1.17(4) mL
62 mV
22.07(7) mL
5.01(2) mL
56 mV
28.36(2) mL
10.00(8) mL
50 mV
36.58(9) mL
Data
Concentration