Aim -
Determination of Calcium from irrigation water sample.
Principle -
When disodium salt of is added to water containing both calcium + magnesium is a determine separately with calcon indicator with 10% solution. Sodium EDTA forms a stronger Complex with calcium the the solution changes from Pink to blue colour. Record the volume of standard edit for calculating calcium in water.
Reagents -
1) EDTA SOLUTION (0.01N) -
Weigh 2 gram versenate (disodium hydrogen EDTA) dissolve it in distilled water make up volume 1 litre.
2) Sodium hydroxide (10%) -
10 gram is NaoH dissolved in distilled water and make the volume hundred ml.
3) Calcon indicator -
Dissolve 20 ml gram of calcon in 50 ml of methanol (or ethanol).
4) Potassium ferrocyanide (K4fe(cn)6) -
Dissolve 4 gm potassium ferrocyanide in hundred ml distilled water.
5)Hydroxylamine hydrochoride (NH4oH. Hcl) -
Dissolved 5 gram hydroxylamine hydrochloride in hundred ml distilled water.
6)Triethanolamine -
TEA indicator reagent grade.
Procedure -
- Take 10ml of water sample in clean hundred ml conical flask and add 25 ml distilled water.
- Add 10 drops of each hydroxylamine hydrochloride potassium ferrocyanide and triethanolamine.
- Add approximately 5ml or enough 10% NaoH solution to raise PH to 12 and 5 drops of calcon indicator prepared freshly shake the content well.
- Titrate the content with standard EDTA solution till pink colour changes blue.
- Record the volume of standard EDTA used.
- Run the blank simultaneously using 10 ml distilled water in place of sample.
- Use all Regent and titrate.
Calculation
Sample reading - blank reading = true reading of EDTA required.
Formula
ca²++ m.eq./lit. =
N. of EDTA × volume of EDTA required ×1000
÷ volume of aliquote taken.
Ca²+ m.eq./lit. = 0.01 × volume of EDTA required × 1000
÷ volume of aliquote taken.
Ca++ m.eq ./lit. = -------
Results
Calcium of given water sample is -------m. eq./lit.
Now we can easily calculate mg²+ by subtracting value of ca²+ from (ca²+ + mg² +)
Comments
Post a Comment