CHEMISTRY INVESTIGATORY PROJECT
COMPARITIVE STUDY OF COMMERCIAL ANTACIDS
A Project Report
Submitted by
TAARUNIKA J
IN
CHEMISTRY
AT
SRI CHAITANYA TECHNO SCHOOL
MUNNEKOLALA , MARATHAHALLI OUTER RING ROAD , BENGALURU-37
2017-18
CHEMISTRY INVESTIGATORY PROJECT
COMPARITIVE STUDY OF COMMERCIAL ANTACIDS
A Project Report
Submitted by
BHAVANA. J
IN
CHEMISTRY
AT
SRI CHAITANYA TECHNO SCHOOL
MUNNEKOLALA , MARATHAHALLI OUTER RING ROAD , BENGALURU-37
2017-18
COMPARTIVIVE STUDY OF COMMERCIAL ANATCIDSCOMPARTIVIVE STUDY OF COMMERCIAL ANATCIDS
COMPARTIVIVE STUDY OF COMMERCIAL ANATCIDS
COMPARTIVIVE STUDY OF COMMERCIAL ANATCIDS
ACKNOWLEDGEMENT
It is my foremost duty to express my deep regards and gratitude to my chemistry teacher Mrs.Vishnu Vandana under whose guidance and supervision I am able to undertake this project. It is her who has been my primary source of inspiration and who motivated, guided and encouraged me at different stages of this project.
I am also thankful for the help rendered by the lab assistant Mr.Kurumurthy who made available the various lab apparatus and chemicals needed for the experiment, else it would have been difficult to perform this project successfully.
I sincerely express my gratitude to our principal Mr.G.Srinivas Rao who pushed us forward to make this project a grand success.
INDEX
Serial No.
CONTENT
PAGE NO.
ACKNOWLEDGEMENT
I
INTRODUCTION
1
II
OBJECTIVE
7
III
THEORY
8
IV
MATERIALS REQUIRED
11
V
PROCEDURE
13
VI
OBSERVATION
17
VII
SUMMARY AND CONCLUSION
19
VIII
BIBLIOGRAPHY
20
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
If the antacid contains NaHCO3 then the reactions that occur in the stomach are:
Na++HCO3-
+H+
+Cl-
NaCl+H2CO3
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 sodium-containing 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-phosphate-complexes, 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 be deleterious for arterial hypertension, heart failure and many renal diseases.
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
The following were the materials required for the project:
a. Apparatus:
1. Burette(50ml)
2. Pipette(20ml)
3. Conical Flasks(250ml)
4. Measuring Cylinder(10ml)
5. Beakers(100ml)
6. Standard Flasks(100ml)
7. Filter Paper
8. Funnel
9. Bunsen Burner
10.Weighingmachine
11.Clean&glazedwhitetile
12.GlassRod
13.Water
14.Crusher
b. Chemicals:
1. NaOH powder
2. Na2CO3powder
3. 10Mconc.HClacid
4. Four different brands of antacids
5. Phenol pthalein
6. Methyl Orange
Na2CO3Powder
NaOHPowder 10MHClSolution
Antacids Phenolpthalein Solution
V.PROCEDURE
1. Firstprepareapproximately1litreofapproximatelyN/10solutionof HClbydiluting10mlofthegiven10MHClacid to1litre.
10ml-10MHCl
Approx.1L H2O
1L-0.1MHCl
2. Nextprepare1litreofapprox.N/10NaOHsolutionbydissolving4.0gof
NaOH powder to make1litreofsolution.
4.0gNaOH
Approx.1L H2O
1L-0.1MHCl
3. Similarly prepare N/10Na2CO3 solution by weighing exactly1.325g of anhydrous Na2CO3 and then dissolving it in water to prepare exactly 0.25L or 250ml of Na2CO3 solution.
4. Now, standardize the HCl solution by titrating it against the standard
Na2CO3 solution using methyl orange as indicator.
Burette:0.1NHCl
Flask:
0.1NNa2CO3+ Methyl Orange
5. Similarly standardize the NaOH solution by titrating it against standardized HCl solution using phenolopthalein as indicator .Stop the titration when the pink color of the solution disappears.
Burette: 0.1NHCl
Flask:0.1NNaOH+
Phenolpthalien
6.Now, powder the four antacid sample sand weigh0.5g of each.
1.0g
7.Add 25ml of the standardized HCl to each of the weighed samples taken in conical flasks .Make sure that the acid is in slight excess
So that neutral is e all the basic character of the tablet powder.
25ml0.1NHCl
8.Add a few drops of phenolphthalein indicator and warm the flask over a bunsen burner till most of the powder dissolves.
9. Filter the insoluble material.
10.Titrate this solution against the standardized NaOH solution , till a permanent pink colour is obtained.
11.Repeat the same experiment for all other samples too.
VI.OBSERVATIONS
Standardisation of HCl solution:
Volume of 0.1N Na2CO3 taken = 20 ml
Indicator used = Methyl Orange
SERIAL
No.
BURETTE READINGS
VOLUME OF ACID USED (ml)
INITIAL READING
FINAL READING
1.
2.
0
18
17
35
17
17
Applying normality equation,
N1 V1 = N2 V2
(acid) (base)
N1 x 17 = 0.1 x 20
Normality of HCl, N1= 2/17 = 0.11 0.1
Standardization of NaOH Solution:
Volume of the given NaOH solution taken = 20.0 ml
Indicator used = Phenolphthalein
SERIAL
No.
BURETTE READINGS
VOLUME OF ACID USED (ml)
INITIAL READING
FINAL READING
1.
2.
0
17
16
33
16
16
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 = 0.5 g
Volume of HCl solution added = 30 ml
Volume of sample solution taken = 20 ml
for titration
ANTACID
VOLUME OF (NaOH) USED FOR NEUTRALIZING UNUSED (HCL)
1.Eno Pineapple
2. Eno Lemon
3.Digene Lime
4.Omez
5. Pephyrous
6. Gelusil
29
24
9
24
40
22
VII.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.
VIII.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
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