cbse xii chemistry project sterilization of water using bleaching powder

7/25/2019 Cbse Xii Chemistry Project Sterilization of Water Using Bleaching Powder

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STERILIZATION OF

WATER USING

BLEACHING POWDER

A CHEMISTRY INVESTIGATORY PROGECT

ANSHUL KUMAR PANDEY

XII B

[THIS PROJECT LOOKS AT THE TECHNIQUE CALLED

STERILIZATION OF WATER USING BLEACHING POWDER

WHICH IS USED TO PURIFY WATER AND MAKES IT FIT FOR

DRINKING.]

Downloaded From: http://www.cbseportal.com
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INDEX

1. Certificate of Authenticity

2. Acknowledgement

3. Introduction

-Nee d of Water

-Purificat ion of Wate r

-Nee d for a sta ble purification t echnique

4. Theory

-Histo ry of Water purification

-Bleaching powde r and its prep arat ion

-Use o f Bleaching powde r in Ste rilizat ion of wat er

5. Experiment

-Aim

-Pre-Req uisite Know ledge

-Requirements

-Procedure

6. Result

7. Bibliography



3/17

CERTIFICATE OF AUTHENTICITY

This is to cer tify that Anshul Kumar Pand e y, a s tu de nt of class XII has successfully

complet ed t he resea rch project on t he to pic Ste rilization o f Wate r by using

Ble aching Pow de r under th e gu ida nce o f Mrs. Mohini Belani (Sub ject Tea cher).

This pro ject is ab solute ly ge nu ine an d doe s no t indu lge in plagiarism of an y kind .

The reference s taken in making this project ha ve b ee n de clare d at t he e nd of this

report.

Signa tu re ( Sub ject Teache r) Signa ture ( Exam ine r)



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ACKNOWLEDGEMENT

I fee l pro ud t o p rese nt my Invest igato ry project in Che mistry on th e topic Ste rilization

of Wate r using Blea ching po wde r which aims at using Blea ching powde r as a

disinfecta nt a nd p urifier t o make wate r fit for drinking.

This project wo uldnt ha ve b ee n feasible witho ut t he prope r and rigorous guida nce o f

my Che mistry tea cher Mrs. Mohini Belani who guide d m e thro ughout this project in

every possible way. An invest igato ry project involves various d ifficult lab expe rime nt s

which have to be carried out by the stude nt to obtain the observations and conclude

the repo rt o n a m ea ningful no te . These experime nts are very critical an d in th e case of

failure , may result in disastrou s conse que nce s. The reb y, I would like to t ha nk both

Mrs.Belani and Lab Asst.Mr.Rajkum ar for guiding me on a ste p by step basis an d

ensuring that I comp lete d a ll my experime nts with ea se.

Rigorous hard wo rk has be e n pu t in th is project to en sure t hat it proves to b e t he best. I

hope tha t th is project will prove to be a bree ding groun d for the n ext gene ration o f

stude nts a nd will guide the m in e ve ry possible way.



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INTRODUCTION

Need o f water

Wate r is an imp orta nt and esse ntial ingredient in our que st for survival on th is plane t.

It is very esse nt ial for carrying out various me ta bo lic proce sses in our bo dy and a lso t o

carry ou t He mo globin througho ut the bo dy.

A daily average of 1 gallon per man is sufficient for drinking and cooking purposes. A

horse, bullock, or mule drinks about 11 gallons at a time. standing up, an average

allowance of 5 gallons should be given for a man, and 10 gallons for a horse or a camel.

An elephant drinks 25 gallons, each mule or ox drinks 6 to 8 gallons, each sheep or pig

6 to 8 pints. These are minimum quantities.

One cubic foot of water = 6 gallons (a gallon = 10 lbs.).

In order to fulfill such a huge demand of water, it needs to be purified and supplied in aorderly and systematic way.

But with t he increasing world po pulation, the de man d for drinking wate r has a lso

increase d d rama tically and the refore it is very essent ial to ident ify resources o f wate r

from which we can use wate r for drinking purpo ses. Many availab le re sources o f water

do not ha ve it in drinkable form. Eithe r the wat e r conta ins excess of Calcium or

Magne sium salts or any other o rganic impurity or it simply con ta ins foreign part icles

which m ake it u nfit a nd unsa fe for Drinking.



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Purificatio n o f Wate r

The re are ma ny me tho ds for the purification of wate r. Som e of the m are

1.Boiling

2.Filtration

3.Blea ching powde r treatm e nt

4.SODIS (Solar Wate r Disinfection)

And the list goe s o n.

Boiling is pe rha ps th e mo st com mo nly used wate r pu rification te chnique in u se tod ay.

While in norma l ho use ho lds it is an e fficie nt t ech nique ; it canno t be use d for ind ustrial

and large scale p urpose s. It is be cause in norm al househ olds, the wate r to b e purified is

very small in qu ant ity and hen ce th e wat er loss due to e vap orat ion is almost n egligible.

But in Indust rial or large scale purification of wate r th e wate r loss du e to evapora tion

will be qu ite high an d the am ou nt o f purified wate r obt aine d will be very less.

Filtra tion is also used for rem oving fore ign pa rticles from wa te r. One ma jor d rawb ack

of this purificat ion p rocess is tha t it cann ot b e used for remo ving fore ign chem icals andimp urities tha t a re miscible with wat er.

SODIS or So lar Wate r Disinfection is re co mm e nde d by the United Natio ns for

disinfection o f wa te r using so ft drink bo ttle s, sunlight, and a black surface -- at least in

hot nations w ith regularly intense sunlight.

Water-filled transparent bottles placed in a horizontal position atop a flat surface in

strong sunlight for around five hours will kill microbes in the water. The process is

made even m ore safe a nd e ffective if the botto m half of the bo ttle or t he surface it 's

lying on is blackened, and/or the flat surface is made of plastic or metal. It's the

combinat ion o f hea t a nd u ltra violet light which kills the organ isms.



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The ma jor dra wback of this pu rification te chnique is tha t it canno t be used in coun trie s

with cold we at her. Also, th e time consu me d for Purification proce ss is mo re a nd it a lso

ne ed s a blackened surface, m uch like solar cookers.

Nee d for a stable purificatio n te chnique

The refore we nee d a purification t echnique w hich can b e use d anytime an d anywhe re,

doe s not requ ire t he use o f any third pa rty cont en t a nd wh ich is also e conom ically

fea sible on bo th norm al scale an d large scale.

Hen ce we loo k at the me tho d of purification o f wat er using the te chnique of treat me nt

by blea ching powde r commo nly known a s Chlorina tion.



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THEORY

History of water purification in different parts of the world.

In 1854 it was discovere d th at a cho lera e pide mic spread t hrough wa ter. The o utb rea k

see me d less severe in area s whe re sand filte rs were insta lled . British scie nt ist Joh n

Snow found tha t t he direct cause of the o utbrea k was wate r pum p contam ination by

sewage wate r. He a pplie d chlorine t o p urify the wate r, and t his paved the way for

wate r disinfection. Since the wate r in the pum p had t aste d and sm elled n orm al, the

conclusion wa s finally drawn tha t good tast e a nd sm ell alone do no t guaran te e safe

drinking wat e r. This discovery le d to governm e nts st art ing to insta ll mu nicipa l wa te r

filte rs (san d filte rs and chlorina tion), an d he nce t he first govern me nt re gulat ion o f

public water.

In th e 18 90s America sta rte d bu ilding large sand filte rs to p rot ect public hea lth . The se

turne d ou t t o be a success. Inste ad o f slow sand filtrat ion, rap id san d filtrat ion was no w

app lie d. Filte r capacity was improved b y clea ning it with po werful je t ste am.

Subse que ntly, Dr. Fulle r found tha t rapid sa nd filtrat ion worked mu ch be tte r whe n it

was precede d by coagulat ion an d sedimen tat ion t echniques. Mean while , such

wate rborne illnesse s as cholera and t ypho id beca me less and less com mo n as wate r

chlorinat ion wo n te rrain thro ughout the world.



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But t he victory ob ta ine d by the inven tion o f chlorinat ion d id no t last long. After some

time the negat ive effects o f this elem en t w ere discovere d. Chlorine vapo rizes much

faste r than wate r, and it was linked to the aggravation a nd cause of respirato ry disea se.

Wate r e xpert s start e d looking for alterna tive wate r disinfectant s. In 1 902 calcium hypo

chlorite an d ferric chloride were mixed in a drinking wa te r sup ply in Belgium , resu lting

in bo th coagulation and disinfection.

The treat men t a nd d istribution of water for safe use is one of the grea test achieveme nts

of the twentieth century. Before cities began routinely treating drinking water with

chlorine (starting with Chicago and Jersey City in US in 1908), cholera, typhoid fever,

dysentery and hepatitis A killed thousands of U.S. residents annually. Drinking water

chlorination and filtration have helped to virtually eliminate these diseases in the U.S.

and o the r developed count ries. Mee ting th e goal of clea n, safe d rinking wate r requires a

multi-barrier approach that includes: protecting source water from contamination,

appropriately treating raw water, and ensuring safe distribution of treated water to

consumers taps. During the treatment process, chlorine is added to drinking water aselem e nta l chlo rine (chlorine gas),

sodium hypochlorite solution o r dry calcium hypochlorite. Whe n a pplie d to wate r, each

of these forms free chlorine , which dest roys path oge nic (disea se -causing) organ ism s.

Almost all systems that disinfect their water use some type of chlorine-based process,

either a lon e o r in com binat ion with o the r disinfectant s. In a ddition to

controlling disease-causing organisms, chlorination offers a number of benefits

including:

Redu ces ma ny disagreea ble t aste s and o dors;

Eliminate s slime bacte ria, mo lds an d a lgae t ha t c om mo nly grow in wate r supp lyrese rvoirs, on th e walls of wate r ma ins an d in storage ta nks;

Rem oves che mical compo unds th at h ave unp lea sant t aste s and hinder disinfection;

and

Helps re mo ve iron a nd ma ngane se from raw wate r.

As imp ort an tly, only chlorine-base d che micals provide residual disinfecta nt levels t hat

preven t m icrobial re-growth an d he lp prote ct treate d wat er t hroughout

the distribut ion system .

For mo re t han a cen tury, the safet y of drinking wate r supplies ha s be en grea tly

improve d by the a ddition o f blea ching powde r. Disinfecting our drinking water e nsure s

it is free of the microorganisms t hat can cause seriou s an d life-thre ate ning disea ses,

such as chole ra an d typho id fever. To t his day, blea ching powde r rem ains the m ost

comm only used drinking wate r disinfectant , and the disinfectant for w hich we have t he



10/17

mo st scient ific inform at ion . Blea ching po wde r is add ed as pa rt of the d rinking wat e r

trea tm e nt proce ss. Howe ve r, blea ching powde r also reacts with t he o rganic matt e r,

na tu rally pre se nt in wat er , such as de caying lea ves. This chemical rea ction form s a

group o f che micals kno wn as d isinfect ion b y-pro ducts. Curre nt scie ntific dat a sho ws tha t

the be nefits of blea ching our d rinking wate r (less disease ) are m uch greate r tha n an y

hea lth risks from THMs an d o the r b y-prod ucts. Altho ugh o the r disinfectant s are

available, blea ching powde r re mains the choice of water tre at me nt experts. When u sed

with mo de rn wa te r filtra tion m et hods, chlorine is effective a gainst virt ually all

microo rganisms. Blea ching powde r is easy to ap ply an d sma ll am ou nts of the che mical

rem ain in the wate r as it tra vels in the distribut ion system from th e tre at me nt plant t o

the consum ers ta p, this le vel of effective ne ss ensure s tha t m icroorganisms cann ot

recontaminate the water after it leaves the tre atm ent .

But what is bleaching powder and how is it prepared?

Blea ching po wde r or Calcium hypoch lorite is a chemical com pound with form ula

Ca(ClO)2. It is wide ly used for wate r trea tm ent an d as a b lea ching agent blea ching

powd er). This che mical is conside red to be relat ively stable a nd has grea te r

availab le chlorine tha n sodium hypochlorite (liqu id b lea ch).

It is pre pa red by either calcium process o r sodium p rocess.

Calcium Proce ss

2 Ca(OH)2+ 2 Cl2 CA(CLO) 2+ CaCl2+ 2 H2O

Sodium Proce ss

2 Ca(OH)2+ 3 Cl2+ 2 NaOH CA(CLO) 2+ CaCl2+ 2 H2O + 2 NaCl



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But how can this chemical be used to steril ize water?

This che mical can be use d for ste rilizing wa te r by Using 5 dro ps of bleach pe r ea ch ha lf

gallon of wate r to be purified , and allowing it t o sit undisturb e d for half an ho ur to ma ke

it sa fe for drinking. Le tt ing it sit se veral hours m ore will he lp re duce the chlorine ta ste ,

as the chlorine will slowly evaporat e o ut .A differe nt re fere nce advises whe n using

house hold blea ch for pu rification; ad d a single d rop o f blea ch pe r qua rt of wat er w hich

is visibly clea r, or th ree drop s pe r qu art of wat e r whe re th e wate r is NOT visibly clea r.

The n allow t he wate r to sit undisturbe d for half an hou r.

What are the actual processes involved in disinfecting and purifying water?

The combinat ion o f following proce sses is used for municipa l drinking wate r treat me nt

worldwide:

1. Pre-chlorination - for algae cont rol and a rrest ing an y biological growt h

2. Aera tion - along with p re-chlorinat ion fo r remo val of dissolve d iron a nd m an gane se

3. Coa gulation - for floccu lat ion

4. Coa gulan t aids also kno wn as polyelectrolyte s - to improve coagulation a nd for

th icker floc form at ion

5. Sedime nta tion - for solids sep arat ion, t ha t is, rem oval of suspen de d solids tra ppe d in

the floc

6. Filtra tion - for rem oval of carrie d o ver floc

7. Disinfection - for killing bacteria

Out of the se processes, th e role of Blea ching powd er is on ly in t he last ste p i.e. forDisinfect ion of water.



12/17

EXPERIMENT

Aim: To Dete rmine the do sage o f ble aching po w de r re quire d for ste rilizatio n o r

disinfe ction o f diffe re nt sam ple s o f wate r.

Requirements: Bure tt e, titrat ion flask, 100ml gradua te d cylinde r, 250m l me asu ring

flask, we ight bo x, glaze d t ile , glass wool.

Bleach ing Powde r, Glass wool, 0.1 N Na2S2O3 solut ion , 10% KI solution, differe nt sam ples

of wate r, starch solution.

Pre -Re quisite Know ledge :

1. A known m ass of the given sam ple o f blea ching powde r is dissolve d in wa te r to

pre pa re a solut ion o f kno wn concent rat ion . This solution cont ains dissolve d chlorine,

libe rate d by the action of blea ching powde r with wate r.

CaOCl2+H20 Ca(OH)2+Cl2

2. The am ou nt o f Chlorine pre sen t in th e abo ve so lution is det e rmine d by trea ting a

known volume of the abo ve solution with e xcess of 10% pot assium iodide so lution,

whe n e quivalent a mo unt of Iodine is libera ted . The Iod ine , thus libe rate d is the n

estimate d b y titrat ing it a gainst a stan dard solution of Sodium t hiosulphate , using

starch so lut ion a s indicato r.

Cl2+2KI 2KCl+I2

I2+2Na2S2O3 Na2S4O6+2NaI

3. A kno wn Volume of one o f the given sam ples of wate r is trea te d with a known

volum e of blea ching po wde r solution. The am oun t o f residua l chlorine is de te rmined

by adding excess pot assium iodide solution and the n t itrat ing against sta nda rdsodium thiosulpha te solution.

4. From t he re ad ings in 2 and 3, the am ou nt o f chlorine a nd he nce blea ching powde r

requ ired for the disinfection of a given volume of the given sam ple o f water can be

calculated.



13/17

Procedure:

1. Prepa ration o f blea ching po wde r solution. We igh accurate ly 2.5g of the given sa mp le

of bleaching powde r and tra nsfer it to a 250m l conical flask. Add a bo ut 100-150m l of

distilled wat er. Sto ppe r the flask and sha ke it vigorously. The suspe nsion th us

ob ta ine d is filte red t hrough glass wool an d the filtra te is dilut ed with water (in a

me asuring flask) to m ake the volume 25 0m l. The so lut ion o bta ine d is 1% bleach ing

powd er solution.

2. Take 20ml of blea ching powde r solution in a st op pe re d conical flask and a dd it to

20m l of 10% KI solut ion . Sto ppe r the flask and sha ke it vigoro usly. Titra te th is

solution against 0.1N Na2S2O3 solution taken in the bure tte . Whe n the solution in the

conical flask be com es light yellow in co lor, add a bout 2m l starch solution . The

solution n ow b eco me s blue in color. Con tinue titrat ing till the blue color just

disappea rs. Repe at the titration to get a set o f three concordant readings.

3. Take 100m l of the wate r sam ple in a 250ml stoppe red conical flask and a dd it to

10ml of blech ing powde r solut ion . The n add 20ml of KI solution and sto pper t he

flask. Shake vigoro usly an d titra te aga inst 0.1N Na2S2O3 solution using sta rch solution

as indicato r as d escribe d in ste p 2.

4. Repe at the step 3 with ot her samp les of water a nd record the observations.



14/17

RESULT

Amo unt of the give n sam ple o f blea ching po wder requ ired to disinfect on e litre of

water

Sample I = g

Sample II= g

Sample III= g



15/17

BIBLIOGRAPHY

1.The Medical front-"Wate r Sup ply"

http://www.vlib.us/medical/sancamp/water.htm

2. Chemistry Projects

http://www.cbseportal.com

3.How to live on Very,Very Little-"Clean d rinking wa te r: How to de velop low co st

sources of drinking wate r just abou t anywhe re"

http://www.jmooneyham.com/watp.html

4.Calcium Hypochloride

htt p:// e n.wikipe dia.org/ wiki/ Blea ching_powde r

5.Water Treatm ent

http:/ / en.wikipedia.org/wiki/ Water_treat me nt

6.Bleach

http://en.wikipedia.org/wiki/Bleach

7.Drinking Wate r Trea tm e nt :Con tinuous Chlorinat ion



16/17

htt p:// www.ianrp ubs.unl.ed u/ e pub lic/p ages/ pu blicationD.jsp?pu blicationId=358

8.Chlorinat ion of Drinking Wate r

http://www.water-research.net/watertreatment/chlorination.htm

9.Chlorinat ion Of Drinking Wa te r (2)

www.edstrom.com/doclib/mi4174.pdf

10.Wage ne t, L, K. Mancl, and M. Sailus, 1995. "Hom e Wat er Trea tm e nt ,"

North east Regiona l Agricultural Enginee ring Service, Coo pe ra tive Extension ,

Itha ca , N.Y.

11."Trea tm e nt Syste ms for Househo ld Wat er Supplies: Chlorina tion,"

North Dakota State University Extension Service

12."Wate r Trea tm e nt Note s: Chlorinat ion of Drinking Water,"

Corne ll Coo pe ra tive Extension , New York Sta te College of Human Ecology,USA

13."Drinking Wate r Stand ard s,"

www.epa.gov/safewater/mcl.html

14."Understanding the New Consumer Confidence Report,"

www.awwa.org/Advocacy/bluethumb98/consumer.cfm



17/17

15."Testing for Drinking Water Quality," NebGuide G89-907 Cooperative

Extension,

Inst itu te of Agriculture an d Nat ura l Resource s, Univers ity of Nebra ska-

Lincoln,USA

16.DISINFECTING YOUR WELL WATER: SHOCK CHLORINATION

http://www.fcs.uga.edu/pubs/PDF/HACE-858-4.pdf


cbse xii chemistry project sterilization of water using bleaching powder

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