9. TO DETERMINE TOTAL IRON IN GIVEN WATER

REQUIREMENTS:

APPARATUS REQUIRED:

1. Measuring cylinder
2. Beaker
3. Spectrophotometer
4. Cubute
5. Conical flask

CHEMICAL REQUIRED:

1. Conc.HCL
2. Ammonium acetate butter
3. Hydroxylamine HCL
4. Pheno throline solution
5. Standard iron solution

THEORY:

Iron is second most abundant metal in the earth crust of which it accounts for 5%(about) elemental iron is rarely found in nature.

          Iron has (as Fe²⁺) concentration of mg/l can be detected by test in distilled solid water. In a minilariced spring water with a total dissolved solid content of 500 mg/l the taste threshold value was 0.12mg/l. In well water,iron concentration below 0.3 mg/l were characterized as unaticacle as level of 01–3 mg/l were found acceptable. In drinking water supplies iron (II) salts are unstable and are precipitated as insoluble iron (III) hydroxide which settles out as a rust coloured fit.

Benefits of Iron:

Iron is used as constructional material for drinking water pipes. Iron oxides are used as pigment in points and plastics. Other compounds are used as food colours and for the treatment of iron deficiency humans. Various iron salts are used as coagulation in water treatment.

PROCEDURE:

First of all, 50ml of water was taken and then 2 ml of conc.HCL and 1ml of hydroxy lamine hydrochloride was added onto it. Some glass beads were added in the flask and then it was heated and then was cooled 10ml of ammonium acetate buffer was added. Then 4ml of phenanthroline. Orange red colour appeared and the solution was kept for cominutes. The reading of the spectrophotometer was taken at 510 nm. The concentration of iron was directly calculated from the standard curve. 

OBSERVATION TABLE:

Concentration (x)	Absorbance (y)
0.1 mg/l	0.02
0.2 mg/l	0.022
0.3 mg/l	0.032
0.4 mg/l	0.035
0.5 mg/l	0.057
0.6 mg/l	0.059
0.7 mg/l	0.101
0.8 mg/l	0.111
0.9 mg/l	0.119
1.0	0.153

CALCULATION:

From the graph

(x₁y₁) = (0.1,0.002)

(x₂y₂) = (0.5,0.08)

now, equation of straight line

y-y₁ = y₂-y₁/x₂-x₁

or, (y-0.02) = (0.08-0.02/0.5-0.1) (x-0.1)

or, 0.4(y-0.02) = 0.06(x-0.1)

or, 0.4 y-0.06x= – 0.006+0.008

or, y= 0.005 + 0.15 x equation (1)

Now,

Comparing above equation with slope intercept for as

  y= mx+c, we get

c= 0.05

m= 0.15

And the absorbance of water sample was found 0.053. At last, concentration of iron can be determined by y

      y= mx+c

      x= 0.053 – 0.005/0.15

= 0.38607 mg/l

Where, 

y= absorbance of water

c= constant

x= concentration of iron

m= slop

RESULT AND DISCUSSION:

The concentration of iron in given water sample (underground) was found to be 0.38667 mg/l

CONCLUSION:

            Hence the total iron content in the given tap water sample was determined with the help of spectrophotometer.