CHEMISTRY INVESTIGATORY
PROJECT
COMPARITIVE STUDY OF
COMMERCIAL ANTACIDS
A Project Report
Submitted by
DT
IN
CHEMISTRY
AT
KENDRIYA VIDYALAYA NO,1,SEC-30,GANDHINAGAR
2016-17
CERTIFICATE
This is to certify that DT of Grade XII,Kendriya
Vidyalaya No.1,Sec-30,GNR has satisfactorily
completed the project in CHEMISTRY on
COMPARITIVE STUDY OF COMMERCIAL
ANTACIDS in the year 2016-17.
Signature of the
Candidate
Signature of the
Principal
Signature of the
Teacher In-Charge
Signature of the
External Examiner
COMPARTIVIVE STUDY
OF COMMERCIAL
ANATCIDS
ACKNOWLEDGEMENT
The enduring pages of the work are the cumulative sequence of extensive guidance
and arduous work. I wish to acknowledge and express my personal gratitude to all
those without whom this project could not have been reality.
First and foremost, I would like to express my deep gratitude to our principal,
Mr.V.P Mishra for providing us with state of the art laboratories and infrastructure
and also providing her valuable suggestions and feedback, which were instrumental
in shaping up the project work. Without her help, this project would remain
unaccomplished.
I would like to sincerely thank our chemistry faculty Mrs. Meena Nair for
spending their precious time with us enhancing our knowledge regarding
project.Their help is unforgettable as this project is built on the concepts that they
have taught us. They always motivated us and ensured that we were on the right
track.
My heartfelt thanks to my parents and other family members who have constantly
motivated and supported me during the making of this project work.
This project would be incomplete without thanking my peers who always lent a
helping hand and showed true spirit of unity and friendship.
I would also like to extend my heartfelt gratitude to the authors and publishers of
the books and managements of the websites, we referredto(as in Bibliography), for
having provided us with us valuable information.
Signature of the student
ABBREVIATIONS
Abbreviations
Expansions
pH
GERD
N/10
Ml
OTC
H-2
Aq
HOMO
LUMO
Power of hydrogen ion
Gastric esophageal reflux disease
0.1 normal
Milliliters
Over the counter
Histamine-2
aqueous
Highest occupied molecular orbit
Lowest unoccupied molecular orbit
Chemical formulae
Expansions
HCl
NaOH
Na2CO3
H3O+/H+
H2SO4
HSO4ClH2O
OH-
Hydrochloric acid
Sodium hydroxide
Sodium carbonate
Hydronium ion
Sulphuric aid
Bisulphate ion
Chloride ion
Water
Hydroxyl ion
INDEX
Serial No.
CONTENT
PAGE NO.
I
INTRODUCTION
1
II
OBJECTIVE
7
III
THEORY
8
IV
MATERIALS
REQUIRED
13
V
PROCEDURE
15
VI
PRECAUTIONS
19
VII
OBSERVATIONS
21
VIII
RESULT
24
IX
SUMMARY
25
X
BIBLIOGRAPHY
26
INTRODUCTION
It is well known that the food we take undergoes a series of complex reactions
within the body which constitute digestion and metabolism. These reactions are
catalyzed by enzymes which are very specific in their action and can function
properly only when the pH of the medium is within a specific range.
Some enzymes require mildly alkaline conditions while others operate only in
weakly acidic media. Amongst the latter category of enzymes are the enzymes that
control the digestion of proteins present in the food as it reaches the stomach. In the
stomach, dilute hydrochloric acid is secreted and it provides mildly acidic
conditions required for the functioning of protein digesting enzymes in the stomach.
Gastric acid is a digestive fluid, formed in the stomach. It has a pH of 1.5 to 3.5 and
is composed of 0.5 % hydrochloric acid (HCl). It is produced by cells lining the
stomach, which are coupled to systems to increase acid production when needed.
Other cells in the stomach produce bicarbonate to buffer the acid, ensuring the pH
does not drop too low (acid reduces pH). Also cells in the beginning of the small
intestine, or duodenum, produce large amounts of bicarbonate to completely
neutralize any gastric acid that passes further down into the digestive tract. The
bicarbonate-secreting cells in the stomach also produce and secrete mucus. Mucus
forms a viscous physical barrier to prevent gastric acid from damaging the stomach.
However, sometimes the stomach begins to secrete an excess of HCl. This leads to a
condition known as Gastric Hyperacidity. This condition can also be triggered by
the intake of to much food or highly spiced food. This, in turn, makes the stomach
lining cells to secrete more acid resulting in Hyperacidity. It also leads to acute
discomfort due to indigestion.
To counter this situation, substances like Antacids or literally anti - acids, have been
developed. Antacids are commercial products that neutralize the excess acid in the
stomach providing a sensation of relief to the person. The action of antacids is
based on the fact that a base can neutralize an acid forming salt and water.
Common antacids satisfy the condition – right amount of alkali that can neutralize
the acid. If the content of alkali in the antacid is too high, no doubt acidity is
relieved, but it’ll create alkaline conditions that makes the digestive enzymes
ineffective.
To make sure that the pH of the stomach remains in a specific range, many
substances are added to the antacids.
Working of Antacids
IftheantacidcontainsNaHCO3thenthereactionsthatoccur
inthestomachare:
Na++HCO3- +H+ +ClH2CO3
NaCl+H2CO3
H2O+CO2
The excess Na+ and HCO3-ions are absorbed by the walls of the small intestines as the food
passes through
The H2CO3 formed during the reaction decomposes rapidly to form water and carbon
dioxide gas.
Types of Antacids
 Sodium Antacids (Alka-Seltzer, Bromo-Seltzer and Others): Sodium bicarbonate
(commonly known as baking soda) is perhaps the best-known of the sodiumcontaining antacids. It is potent and fast-acting. As its name suggests, it is high in
sodium. If you're on a salt-restricted diet, and especially if the diet is intended to treat
high blood pressure (hypertension), take a sodium-containing antacid only under a
doctor's orders.
 Calcium Antacids (Tums, Alka-2, Titralac and Others):Antacids in the form
of calcium carbonate or calcium phosphate are also potent and fast-acting. Regular or
heavy doses of calcium (more than five or six times per week) can cause constipation.
Heavy and extended use of this product may clog your kidneys and cut down the
amount of blood they can process. Extended use of calcium antacids can also
cause kidney stones.
 Magnesium Antacids (Maalox, Mylanta, Riopan, Gelusil and Others):Magnesium
salts come in many forms -- carbonate, glycinate, hydroxide, oxide, trisilicate, and
aluminosilicate. Magnesium has a mild laxative effect; it can cause diarrhea. For this
reason, magnesium salts are rarely used as the only active ingredients in an antacid,
but are combined with aluminum, which counteracts the laxative effect. (The brand
names listed above all contain magnesium-aluminum combinations.) Like calcium,
magnesium may cause kidney stones if taken for a prolonged period, especially if the
kidneys are functioning improperly to begin with. A serious magnesium overload in
the bloodstream (hypermagnesaemia) can also cause blood pressure to drop, leading
to respiratory or cardiac depression -- a potentially dangerous decrease in lung or
heart function.
 Aluminum Antacids (Rolaids, ALternaGEL, Amphojel and Others): Salts of
aluminum (hydroxide, carbonate gel, or phosphate gel) can also cause constipation.
For these reasons, aluminum is usually used in combination with the other three
primary ingredients. Used heavily over an extended period, antacids containing
aluminum can weaken bones, especially in people who have kidney problems.
Aluminum can cause dietary phosphates, calcium, and fluoride to leave the body,
eventually causing bone problems such as osteomalacia or osteoporosis.
Side effects
 Calcium: Excess calcium from supplements, fortified food and high-calcium diets,
can cause milk-alkali syndrome, which has serious toxicity and can be fatal.
 Carbonate: Regular high doses may cause alkalosis, which in turn may result in
altered excretion of other drugs, and kidney stones. A chemical reaction between the
carbonate and hydrochloric acid may produce carbon dioxide gas. This causes gastric
distension which may not be well tolerated. Carbon dioxide formation can also lead to
headaches and decreased muscle flexibility.
 Aluminum hydroxide: May lead to the formation of insoluble aluminium-phosphatecomplexes,
with
a
risk
for hypophosphatemia and osteomalacia.
Although aluminium has a low gastrointestinal absorption, accumulation may occur
mainly in the presence of renal insufficiency. Aluminium-containing drugs often
cause constipation and are neurotoxic.
 Magnesium hydroxide: Has laxative properties. Magnesium may accumulate in
patients with renal failure leading to hypermagnesaemia, with cardiovascular and
neurological complications.
 Sodium: increased intake of sodium may
hypertension, heart failure and many renal diseases.
be
deleterious
for arterial
 Heartburn, reflux, indigestion, and sour stomach are a few of the common terms used
to describe digestive upset. Self-diagnosis of indigestion does carry some risk because
the causes can vary from a minor dietary indiscretion to a peptic ulcer.
 The pain and symptoms of GERD or simply "reflux", may mimic those of a heart
attack. Misdiagnosis can be fatal. A bleeding ulcer can be life threatening.
 GERD and pre-ulcerative conditions in the stomach are treated much more
aggressively since both, if untreated, could lead to esophageal or stomach cancer.
 It is primarily for this reason that the H2 blockers including cimetidine (Tagamet),
famotidine (Pepcid), and ranitidine (Zantac), and the proton pump inhibitor (PPI)
omeprazole (Prilosec) were made OTC.
 These drugs stop production of stomach acid and provide longer lasting relief but they
do not neutralize any stomach acid already present in the stomach.
Problems with reduced stomach acidity
 Reduced stomach acidity may result in an impaired ability to digest and absorb
certain nutrients, such as iron and the B vitamins. Since the low pH of the stomach
normally kills ingested bacteria, antacids increase the vulnerability to infection. It
could also result in the reduced bioavailability of some drugs. For example, the
bioavailability of ketocanazole (anti-fungal) is reduced at high intragastric pH (low
acid content).
Over usage of antacids naturally have side-effects. As with anything in life, it must be used
in moderation. The following flowchart elucidates very clearly.
II.OBJECTIVE
This project aims at analyzing some of the commercial antacids to determine
which one of them is the most effective by conducting a quantitative analysis.
Motives behind selecting this research project:
 Consumerism, in the era of global industrialization, plays a very important role.
There are various product options available for consumers to choose from.
Different manufacturers selling their products, attempting to sway public
opinion in their favor, marketing their products regardless of their effectiveness
in functionality. Hence it becomes the consumer’s right to experiment and
know the most effective, efficient, and value for money product. There are
various methods to conclude that a product out of all the given competitors is
the best. Experimental research is the most rational and convincing one of those
methods. The result of this analysis could be used to inform oneself as to which
antacid is the best and provides best relief.
 Apart from the economic perspective, the titrations that are conducted as a part
of this experiment is in itself an attracting aspect. The prospect of making color
changing solutions, the thrill of chemical reactions, and conducting them with
accuracy is probably the most interesting part of titrations and the whole
project.
III.THEORY
Antacids react with excess stomach acid by neutralization.
i.e. HCl + NaOH → H2O + NaCl
During the process, hydrogen ions H+ from the acid (proton donor) or a hydronium ion
H3O+ and hydroxide ions OH Θ from the base (proton acceptor) react together to form a
water molecule H2O. In the process, a salt is also formed when the anion from acid and the
cation from base react together. Neutralization reactions are generally classified as
exothermic since heat is released into the surroundings.
Acids are proton donors which convert into conjugated bases. They are generally pure
substances which contain hydrogen ions (H+) or cause them to be produced in solutions.
Hydrochloric acid (HCl) and sulfuric acid (H2SO4) are common examples. In water, these
break apart into ions:
HCl → H+(aq) + ClΘ(aq) OR
H2SO4 → H+(aq) + HSO4Θ(aq)
Bases are proton acceptors which convert into conjugated acids. They are generally
substances which contain hydroxide ion (OHΘ) or produce it in solution. Alkalis are the
soluble bases, i.e. a base which contains a metal from group 1 or 2 of the periodic table. To
produce hydroxide ions in water, the alkali breaks apart into ions as below:
NaOH→ Na+(aq) + OHΘ(aq)
Examples of bases include sodium hydroxide (NaOH), potassium hydroxide (KOH),
magnesium hydroxide (Mg(OH)2), and calcium hydroxide (Ca(OH)2). Antacids are
generally bases.
Explanation of action of neutralization of antacids :
The Lewis definition of acid-base reactions is a donation mechanism, which
conversely attributes the donation of electron pairs from bases and the acceptance by
acids.
Ag + + 2 :NH3 → [H3N :Ag: NH3]+
(A silver cation reacts as an acid with ammonia which acts as an electron-pair donor,
forming an ammonia-silver adduct)
In reactions between Lewis acids and bases, there is the formation of an adduct whenthe
highest occupied molecular orbital (HOMO) of a molecule, such as NH3 withavailable lone
electron pair(s) donates lone pairs of electrons to the electron-deficientmolecule's lowest
unoccupied molecular orbital (LUMO)through a co-ordinate covalent bond; in such a
reaction, the HOMO-interacting molecule acts as a base, and the LUMO-interacting
molecule acts as an acid. In highly-polar molecules, such as boron trifluoride (BF3), the
most electronegative element pulls electrons towards its own orbitals, providing a more
positive charge on the less-electronegative element and a difference in its electronic
structure due to the axial or equatorial orbiting positions of its electrons, causing repulsive
effects from lone pair-bonding pair (Lp-Bp) interactions between bonded atoms in excess of
those already provided by bonding pair-bonding pair (Bp-Bp) interactions.
Determination of concentrations of substances in neutralization:
The experimental method about neutralization is the acid-base titration. An acid- base
titration is a method that allows quantitative analysis of the concentration of an unknown
acid or base solution. It makes use of the neutralization reaction that occurs between acids
and bases, and that we know how acids and bases will react if we know their formula.
Before starting the titration a suitable pH indicator must be chosen. In this project,
phenolphthalein is chosen. The endpoint of the reaction, the point at which all the
reactants have reacted, will have a pH dependent on the relative strengths of the acid and
base used. The pH of the endpoint can be estimated using the following rules:
• A strong acid will react with a strong base to form a neutral (pH=7) solution.
• A strong acid will react with a weak base to form an acidic (pH<7) solution.
• A weak acid will react with a strong base to form a basic (pH>7) solution.
Phenolphthalein is used to determine the end point of the titration which indicates complete
neutralization. In the presence of, an acid solution is colourless, a basic solution is very dark
pink, and a neutral solution is very pale pink. At this point the solution is very slightly basic,
with a negligible amount of excess NaOH. By keeping track of exactly how much NaOH is
needed to complete the neutralization process, the amount of HCl originally neutralized by
the antacid can be calculated. The difference between the number of moles of HCl initially
added to the antacid and the number of moles of HCl neutralized by the NaOH during the
titration is the number of moles neutralized by the antacid. Several antacids will be tested
and the relative strengths of each will be compared.
Nature of phenolphthalein:
Phenolphthalein is a chemical compound with the formula C20 H14 O4. It is insoluble in
water, and is usually dissolved in alcohols for use in experiments. It is itself a weak acid,
which can lose H+ ions in solution. The phenolphthalein molecule is colorless. However, the
phenolphthalein ion is pink. When a base is added to the phenolphthalein,the molecule⇌
ions equilibrium shifts to the right, leading to more ionization as H+ ions are removed. This
is predicted by Le Chatelier's principle.
++++++++++++++++++++++ HYPOTHESIS+++++++++++++++++++++++++
Our hypothesis is that the greater proportion of the active ingredient with stronger base
in an antacid tablet will have the greater neutralizing power. And thus, it will be more
effective to cure upset stomach.
IV.MATERIALS REQUIRED
Thefollowingwerethematerialsrequiredfortheproject:
a.Apparatus:
1. Burette(50ml)
2. Pipette(20ml)
3. ConicalFlasks(250ml)
4. MeasuringCylinder(10ml)
5. Beakers(100ml)
6. StandardFlasks(100ml)
7. FilterPaper
8. Funnel
9. BunsenBurner
10.Weighingmachine
11.Clean&glazedwhitetile
12.GlassRod
13.Water
14.Crusher
b.Chemicals:
1. NaOHpowder
2. Na2CO3powder
3. 10Mconc.HClacid
4. Fourdifferentbrandsofantacids
5. Phenolpthalein
6. MethylOrange
Na2CO3Powder
NaOHPowder
Antacids
10MHClSolution
Phenolpthalein Solution
V.PROCEDURE
1. Firstprepareapproximately1litreofapproximatelyN/10solutionof
HClbydiluting10mlofthegiven10MHClacid to1litre.
Approx.1L H2 O
10ml-10MHCl
1L-0.1MHCl
2. Nextprepare1litreofapprox.N/10NaOHsolutionbydissolving4.0gof
NaOHpowderto make1litreofsolution.
4.0gNaOH
Approx.1L H2O
1L-0.1MHCl
3. SimilarlyprepareN/10Na2CO3solutionbyweighing
exactly1.325gofanhydrousNa2CO3andthendissolvingitinwatertoprepareexactly0.25
Lor250mlofNa2CO3solution.
4. Now,standardizetheHClsolutionbytitratingitagainst thestandard
Na2CO3solutionusingmethylorangeasindicator.
Burette:0.1NHCl
Flask:
0.1NNa2CO3+ MethylOrange
5.
SimilarlystandardizetheNaOHsolutionbytitratingitagainststandardizedHClsolutio
nusingphenolopthaleinasindicator.Stopthetitration when
thepinkcolorofthesolutiondisappears.
Burette: 0.1NHCl
Flask:0.1NNaOH+
Phenolpthalien
6.Now,powderthefourantacidsamplesandweigh0.5gofeach.
1.0g
7.Add25mlofthestandardisedHCltoeachoftheweighedsamplestakeninconicalflasks.M
akesurethattheacidisinslightexcess
sothatneutraliseallthebasiccharacterofthetabletpowder.
25ml0.1NHCl
8.Addafewdropsofphenolpthaleinindicatorandwarmtheflaskoverabunsenburnertillmo
stofthepowderdissolves.
9. Filtertheinsolublematerial.
10.Titratethissolutionagainst
thestandardisedNaOHsolution,tillapermanentpinkishtingeinsobtained.
11.Repeatthesameexperimentforallothersamplestoo.
VI.PRECAUTIONS
1. Avoid touching the antacid with your fingers.
2. Be careful not to lose any solid when crushing the antacid tablet.
3. Avoid touching hot surfaces when working near the hot plate and be
cautious when transporting heated solutions.
4. The hot plate should not be left unattended .
5. Dilute HCl and NaOH were corrosive and can damage your eyes and
cause skin irritation.
6. The burette must be rinsed out with NaOH before use to prevent dilution
of the solution.
7. It should be made sure that there were no air bubbles in the burette tips.
8. Burette readings should be recorded to the nearest 0.05 cm3.
9. Sodium hydroxide should be removed from the burette as soon as
possible after the titration. It was because NaOH is corrosive and it
reacted with carbon dioxide in the air to form sodium carbonate which
was a white solid and clogged the tip of the burette easily.
10.Rinse all apparatus thoroughly using Distilled water. Any residual
chemicals could cause variations in pH readings.
11.Tap on the weighing machine after it shows required value to confirm a
precise reading
12.Pipette out the solutions carefully as it is possible to accidentally ingest
the solution.
VII.OBSERVATIONS
 Standardisation of HCl solution:
Volume of 0.1N Na2CO3 taken = 20 ml
Indicator used = Methyl Orange
SERIAL
No.
BURETTE READINGS
INITIAL READING
FINAL READING
1.
2.
0
18
17
35
Applying normality equation,
N1 V1 = N2 V2
(acid)
(base)
Normality of HCl,
N1 x 17 = 0.1 x 20
N1= 2/17 = 0.11 ≈ 0.1
 Standardization of NaOH Solution:
Volume of the given NaOH solution taken = 20.0 ml
Indicator used = Phenolphthalein
VOLUME OF
ACID USED
(ml)
17
17
SERIAL
No.
1.
2.
BURETTE READINGS
INITIAL READING
FINAL READING
0
17
16
33
Volume of acid used = 16 ml
Applying normality equation,
N1 V’1 = N’2 V’2
(acid)
(base)
0.11 x 16 = N’2 x 20
Normality of HCl, N’2 = (0.11*16)/20 = 0.09 ≈ 0.1
 Analysis of antacid tablets:
 Weight of the antacid tablet powder
 Volume of HCl solution added
 Volume of sample solution taken
for titration
= 0.5 g
= 30 ml
= 20 ml
VOLUME OF
ACID USED
(ml)
16
16
ANTACID
VOLUME OF (NaOH) USED
FOR NEUTRALIZING
UNUSED (HCL)
1.Eno Pineapple
29
2. Eno Lemon
24
3.Digene Lime
9
4.Omez
24
5. Pephyrous
40
6. Gelusil
22
VIII.RESULT
 1g of Eno Pineapple required 29 ml of Sodium Hydroxide (NaOH) to
titrate it completely.
 1 g of Eno Lemon required 24 ml of Sodium Hydroxide (NaOH) solution
to titrate it completely.
 1 g of Digene lime required 9 ml of Sodium Hydroxide (NaOH) to titrate
it.
 1 g of Omez required 24 ml of Sodium Hydroxide (NaOH) to titrate it
completely.
 1 g of Pephyrous required 40 ml of Sodium Hydroxide (NaOH) to titrate
it completely.
 1 g of Gelusil required 22 ml of Sodium Hydroxide (NaOH) to titrate it
completely.
Based on the hypothesis of the experiment, the antacid which requires the least
amount of Sodium Hydroxide (NaOH) is the best antacid. From the recorded
observation, Digene© requires the least (5 ml), and is therefore the best Antacid.
IX.SUMMARY AND CONCLUSION
Antacids play a very important role in relieving many patients suffering from
gastric hyperacidity, commonly referred to as gastritis. This project was
undertaken to analyze the best commercially available antacid according to the
amount of hydrochloric acid they could neutralize.
After exploring many books and websites to find out more about antacids, we
were clear of its role and its applications. We started our project by powdering
the various antacid samples and making sure that the apparatus were clean.
Later we standardized various solutions and prepared N/10 HCl solution and
N/10 NaOH solution. This was done by titrating various solutions and using the
respective indicators.
The powdered antacid samples weighing 1 gram each was each added to 30 ml
of the standardized solution of HCl in separate conical flasks. These solutions
were later titrated with the standardized NaOH and the readings were noted.
These readings were helpful in deciding the amount of HCl that each antacid
could neutralize.
Various antacids could neutralize a specific amount of the acid. pephyrous was
the poorest among all antacids. Eno pineapple had a slightly higher alkaline
nature while Eno lemon and Omez proved to neutralize to same amount .
Gelusil had a higher concentration of the base. Digene had the highest basic
character!
Thus, on the basis of the experiment conducted, it was adjudged that Digene
was the best commercially available antacid.
X.BIBLIOGRAPHY
Websites:
•
http://www.reachoutmichigan.org/funexperiments/quick/csustan/antacid
•
http://icn2.umeche.maine.edu/genchemlabs/Antacid/antacid2.htm
•
http://www.chem.latech.edu/~deddy/chem104/104Antacid.htm
•
http://www.images.google.com
•
http://www.wikipedia.com
•
http://www.pharmaceutical-drug-manufacturers.com
Books
 Comprehensive Practical Chemistry Class XII