Branch Procedure Answer
A Refer to the interferences given in the titration
procedure for the parameter.
If interferences are not
present or thought to not be
present, go to Branch B.
If interferences are present,
go to Branch C.
B Titrate deionized water with no standard
added, then do three standard additions. Refer
to the Accuracy check section of the procedure
for the steps. Record the digits necessary for
each titration. Refer Table 1.
Complete the table with the equation:
Total standard added mg/L = (Total standard
added mL ÷ Sample volume mL) × Standard
concentration mg/L
Where:
Total standard added mL—The volume of
standard at each addition
Sample volume mL—The volume of
deionized water
Standard concentration mg/L—The
concentation of the standard
Example: For the chloride procedure, silver
nitrate method, add 0, 0.1, 0.2, then 0.3 mL of
12,500-mg/L chloride standard to 50.0 mL of
deionized water. Titrate to the end point after
each 0.1 mL standard addition.
The chemicals, apparatus,
procedures and standards
are in good working
condition if the total standard
added (mg/L) increments the
same amount for each
standard addition.
If the expected increments
between the additions are
seen, go to Branch C.
If the results did not give the
expected increments, go to
Branch D.
C Titrate the sample with no standard added,
then do three standard additions. Refer to the
Accuracy check section of the procedure for
the steps. Record the digits necessary for the
titration end point. Refer Table 1. Then,
complete the table with the equation from
Branch B.
If the expected increments
between the additions are
seen, go to Branch G.
If the results did not give the
expected increments, go to
Branch F.
D Carefully check the instructions or directions
for use of the procedure. Make sure that the
correct techniques, reagents, titrant, sample
volume and digit multiplier were used.
Make sure that there is no air or liquid in the
delivery tube other than the titrant. Eject
several drops of titrant.
If the procedure is found to
be in error, do Branch B
again with the correct
procedure.
If the procedure is found to
be correct, go to Branch E.
English 15
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