In the DPD colorimetric method for the free chlorine residual, which is reported
ID: 918583 • Letter: I
Question
In the DPD colorimetric method for the free chlorine residual, which is reported as mg Cl2/L, the oxidizing power of free chlorine converts the colorless amine N,N-diethyl-p-phenylenediamine to a colored dye that absorbs strongly over the wavelength range of 440-580 nm. Analysis of a set of calibration standards gave the following results:
mg Cl2/L absorbance
0.00 0.000
0.50 0.270
1.00 0.543
1.50 0.813
2.00 1.084
A sample from a public water supply is analyzed to determine the free chlorine residual, giving an absorbance of 0.113. What is the free chlorine residual for the sample in mg Cl2/L?
TH2. In the DPD colorimetric method for the free chlorine residual, which is reported as mg Cl2/L the oxidizing power of free chlorine converts the colorless amine N.N-diethyl-p phenylenediamine to a colored dye that absorbs strongly over the wavelength range of 440-580 nm. Analysis of a set of calibration standards gave the following results Anal. Chem 2, Chap, 10, prob. 17) (25 points) mg Cl2/L 0.00 0.50 1.00 1.50 2.00 absorbance 0,000 0.270 0.543 0.813 1.084 A sample from a public water supply is analyzed to determine the free chlorine residual, giving an absorbance of 0.113 What is the free chlorine residual for the sample in mg Cl2/L?Explanation / Answer
SOLUTION:
The concentration shown inred color corresponds to absorbance of 0.113. The corresponding concentration of Cl2 is 0.2mg/L.
Dear candidate we have plotted a graph b/n concentration and absorbance, unfortunately the Q A board cant read excel files. Plot absorbance on y-axis and conc. on x- axis. The check the concentration corresponding to absorbance of 0.113. The answer will be 0.2mg/L