Hardness

Question 1

Maximum sample holding time

Answer 1

28 days, but recommended immediate

Question 2

What titrant is used for hardness

Answer 2

0.01 M EDTA

Question 3

What color will the solution turn when fully titrated

Answer 3

magenta to stable blue

Question 4

What is the multiplication factor used for a volume of 100 mL

Answer 4

10X

Question 5

Frequency of QC standard for Hardness

Answer 5

Monthly

Question 6

What volume of sample is used

Answer 6

50 mL

Question 7

What volume of buffer is used

Answer 7

1.0 mL

Question 8

How much color indicator is used

Answer 8

3 drops

Question 9

Volume of calcium added for standardization

Answer 9

20 mL standard to 30 mL DI water

Question 10

How many replicates are completed for standardization

Answer 10

2 (duplicates)

Question 11

What volume of titrant is acceptable for the standardization blank

Answer 11

less than 0.1 mL (about 2 drops)

Question 12

Standardization acceptance criteria

Answer 12

5% nominal (19.0-21.0 mL titrated)

Question 13

Can a correction factor be applied

Answer 13

no, we use commercially bought EDTA

Question 14

Expiration of reagents and indicators

Answer 14

1 year after opening, or manufacturers exp date