2. Learning The Method of Testing The
Presence Of Arsenic
Arsenic measurement :
1.Certain amount of
sample taken 6.A Mercury strip
inserted. Arsene gas reacts
2.KI (Potassium iodide) with Hg.
added to the sample. 7. Reaction takes about 20
3. 1 tablespoon of Zinc min.
compound powder added.
4. The container is shaken 8.Colour obtained can be
well. matched with data
provided.
5. Colour changes from
purple to grey .
9. The standard level is
1ppm

3. ANALYSIS OF WATER
Portable kit is used:
 Sample: fresh water
body….(stagnant water)
 pH-6.5-8.5 , conductivity-
553uS/cm,
 Salinity- 0
 Dissolved Oxygen- >4

4. Ion Selective Electrode (ISE):
Lanthanum crystal probe to test
concentration of fluoride ion.
10 ml of solution containing fluoride
ion taken.
10 ml Total Ionising Strength
Adjustable Buffer (TISA) added.
Thus, they are in 1:1 ratio.
1.5ppm is considered within safe
levels.
In west Bengal there is a high
fluorite level in Baruipur , Sonarpur,
Thakurpukur areas.

5. Ion selective Electrode Probe for fluoride
ion detection-
•10 ml of sample is taken. Lanthanum crystal
electrode used….
• TISAB( Total Ionising Strength Adjustable
Buffer) is used
•Result- F-1 present – 0.379 mg/l

6. ARSENIC DETECTION
•Procedure- KI is added to sample of contaminated
water- colour changes from colourless to purple.
•Zn added --- changes arsenic from pentavalent to
trivalent
•Compound of Zinc added ----- colour changes to
grey
• Mercuric chloride paper held above but the
solution must not touch it
•If arsine gas come in contact with the paper gas
turns to mercuric arsenate after 20 min black colour
would be seen.
Experiment performed by the students in
the chemistry laboratory at
Geological Survey of India(GSI)

7. Arsenic test kit
Black colouration here
indicates that the sample
contains arsenic.

8. Handling the portable kit probe
Portable Kit Probe As dissolved If less than
is used to oxygen levels 4, then
measure, H+ in water drop water is
conductivity, below 5.0 mg/l, considered For potable
salinity, Mg and aquatic life is to be water pH
Ca ion content, put under stagnating. value lies
stress. between
6.5 to 8.5
Dissolved
oxygen, arsenic For potable For potable
water D.O. is water
content and conductivity is
other around 5.18
less than 1000.
mg/l.
properties of
water sample.

10. Total hardness: Ca and Mg ions contribute
to hardness
The value obtained
10 ml of sample
is the total
taken.
hardness value.
2 drops of
The colour changes
Eriochrome Black T
from pink to light
(EBT) indictor
blue.
added.
NH4Cl (buffer
NH4OH added. solution) added
dropwise.

11. Total Hardness
Titration Method:-
In burette EDTA is taken
•The sample is taken in dish.
•2 drops of EBT indicator is added….Buffer
is mixed……………
•Observation- colour changes from pink to
blue . Hence Mg +2 and Ca+2 are present…..

13. This a short
As If we start our
Water is an survey that we
students, this is mission of
inevitable students had
the most protecting our
source of conducted….
important mother Earth
life…..so being May not be a
approach in right from
children of huge one…but
order to now…..then
mother earth we have been
prevent future
we must never taught that the
mankind from generations will
destroy this many little steps
committing sins be able to live
vibrant heritage of ‘me’ will prove
like causing in harmony with
of her’s. to be the giant
water pollution. the nature…
leap of ‘us’ ….

14. Thank you…
By B.D.M.International