OBJECTIVE

To analyse the given samples of commercial antacids by determining the amount of hydrochloric acid they can neutralize.

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CERTIFICATE

This is certified that this investigatory project has been submitted by Patrick Zolawma Lawlor AISSCE No. as per the partial fulfillment of the CBSE for the year 2010-2011.

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ANTACIDS

An Antacid is any substance, generally a base or basic salt, which neutralizes stomach acidity. They are used to relieve acid indigestion, upset stomach, sour stomach, and heartburn.

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ACTION MECHANISM

Antacids perform a neutralization reaction, i.e. they buffer gastric acid, raising the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gastrointestinal mucosa, they signal pain to the central nervous system. This happens when these nerves are exposed, as in peptic ulcers. The gastric acid may also reach ulcers in the esophagus or the duodenum.

Other mechanisms may contribute, such as the effect of aluminium ions inhibiting smooth muscle cell contraction and delaying gastric emptying.

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INDICATIONS

Antacids are taken by mouth to relieve heartburn, the major symptom of gastro esophageal reflux disease, or acid indigestion. Treatment with antacids alone is symptomatic and only justified for minor symptoms. Peptic ulcers may require H2-receptor antagonists or proton pump inhibitors.

The utility of many combinations of antacids is not clear, although the combination of magnesium and aluminium salts may prevent alteration of bowel habits.

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SIDE EFFECTS

Excess calcium from supplements, fortified food and high-calcium diets, can cause the milk-alkali syndrome, which has serious toxicity and can be fatal. In 1915, Bertram Sippy introduced the “Sippy regimen” of hourly ingestion of milk and cream, the gradual addition of eggs and cooked cereal, for 10 days, combined with alkaline powders, which provided symptomatic relief for peptic ulcer disease. Over the next several decades, the Sippy regimen resulted in renal failure, alkalosis, and hypercalemia, mostly in men with peptic ulcer disease. These adverse effects were reversed when the regimen stopped, but it was fatal in some patients with protracted vomiting. Milk alkali syndrome declined in men after effective treatments were developed for peptic ulcer disease. But during the past 15 years, it has been reported in women taking calcium supplements above the recommended range of 1200 to 1500 mg daily, for prevention and treatment of osteoporosis, and is exacerbated by dehydration. Calcium has been added to over-the-counter products, which contributes to inadvertent excessive intake.

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The New England Journal of Medicine reported a typical case of a woman who arrived in the emergency department vomiting and altered mental status, writhing in pain. She had consumed large quantities of chewable antacid tablets containing calcium carbonate (Tums). She gradually recovered.

Compounds containing calcium may also increase calcium output in the urine, which might be associated with kidney stones. Calcium salts may cause constipation.

Other adverse effects from antacids include:  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 in the presence of renal insufficiency. Aluminium-containing drugs may cause constipation.

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 Magnesium hydroxide : Has laxative properties. Magnesium may accumulate in patients with renal failure leading to hypermagnesemia, with cardiovascular and neurological complications. See Milk of magnesia.

 Sodium : Increased intake of sodium may be deleterious for arterial hypertension, heart failure and many renal diseases.

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REQUIREMENTS 

Burettes, pipettes, titration flasks, measuring flasks, beakers, weight box, fractional weights, sodium hydroxide, sodium carbonate, hydrochloric acid, phenolphthalein.

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PROCEDURE 

 Prepare 1 litre of approximately  HCl solution by diluting 10 ml of the concentrated acid for one litre.

 Similarly, make 1 litre of approximately NaOH solution by dissolving4.0g of NaOH to prepare one litre of solution.

 Prepare  Na2CO3 solution by weighing exactly 1.325 g of anhydrous sodium carbonate and then dissolving it in water to prepare exactly 0.25 litres (250 ml) of solution.

 Standardize the HCl solution by titrating it against the standard Na2CO3 solution using methyl orange as indicator.

 Similarly, standardize NaOH solution by titrating it against standardized HCl solution using phenolphthalein as indicator.

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 Powder the various samples of antacid tablets and weigh 1.0 g of each.

 Add a specific volume of standardised HCl to each of the weighed sample is taken in conical flasks. The acid should be in slight excess, so that it can neutralize all the alkaline component of the tablet.

 Add 2 drops of phenolphthalein and warm the flask till most of powder dissolves. Filter off the insoluble material.

 Titrate this solution against the standardised NaOH solution, till a permanent pinkish tinge is obtained. Repeat this experiment with different antacids.

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CHEMICAL REACTIONS

Standardisation of HCl solution

2HCl + Na2CO3 2NaCl + CO2 +H2O

Standardisation of NaOH solution

HCl + NaOH NaCl + H2O

Analysis of Antacid tablets

Al(OH)3 + 3HCl AlCl3 + 3H2O

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OBSERVATIONS AND CALCULATIONS :

Standardisation of HCl solution Volume of 0.1N Na2CO3 taken for titration

=20 ml Sl No

Burette reading

Initial(ml)

Final(ml)

Volume of acid Used (ml)

1

2

3

0 27.2

27.2 54.5

54.5 81.6

27.2

27.3

27.1

Concordant reading = 27.2Now ,according to Normality equation, we have, N1V1 = N2V2

Where, N1 = Strength of Na2CO3 , N2 = Strength of HClV1 = volume of Na2CO3 , V2 = volume of HCl

Therefore, 0.1 x 20 = N2 x 27.2 or, N2 =0.073215Hence, the strength of HCl is 0.073N

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Standardisation of NaOH solution :

Volume of NaOH taken for titration =20 ml

Sl NoBurette reading

Initial(ml)

Final(ml)

Volume of acid Used (ml)

1

2

3

0 25

25 50.2

50.2 75.5

25

25.2

25.3

Concordant reading = 25.2Now ,according to Normality equation, we have, N1V1 = N2V2

Where, N1 = Strength of NaOH , N2 = Strength of HClV1 = volume of NaOH , V2 = volume of HCl

Therefore, N1 x 20 = 0.1 x 25.2 or, N1 =0.0792515Hence, the strength NaOH of is 0.079N

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Analysis of Antacid tablets: Weight of antacids powder taken = 1.0gms (approx)

Volume of HCl added =27.2ml

Antacidstablets

Vol of NaOH soln.used to nentraliseunused HCl (ml)

Vol of HCl soln. used to neutralise1.0gm of antacid (ml)

Digene

Gelusil

Aciloc

Zintac

10.5

55.6

16.5

17.5

27.2

27.2

27.2

27.2

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RESULT

Thus, Gelusil requires the maximum volume of NaOH for neutralizing the acid in the given proportions of antacids.

0

10

20

30

40

50

60

Antacids

Vol

of

NaO

H(m

l)

1

2

34

Fig:1: Variation of the vol of NaOH used for neutralization of the acid content of the different antacids.Here, 1 = Digene , 2 = Gelusil , 3 = Aciloc , 4 = Zintac

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CONCLUSION

From the fig.1.it is clear that the amount of alkali

present is minimum in Gelusil, as it requires the maximum amount of NaOH for neutralizing the acid.Is understood as principle of the experiment is based on titrating the exess of the acid , which is left after neutralizing the base of the antacid. If more of the acid is used, then less will be remaining unreacted in excess form and hence, less of the alkali will be required for neutralizing it.

Thus, it is clear that the antacid requiring more of the alkali for neutralizing the excess of the acid is more effective as it contains less of alkali and will not produce excess of alkali to the stomach, which might have its own side effects.

From our primary study of commercial antacids, it is concluded that Gelusil is the most effective antacids with minimum side effects.

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BIBILIOGRAPHY

Companion Practical Chemistry , XII

Vogels Quantitative Analysis, 5th Edition, 1996

www.phrama.com

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CONTENTS

1) Objective 1

2)Antacid 2

3)Action Mechanism 3

4)Indications 4

5)Side effects 5

6)Requirements 8

7)Procedure 9

8)Chemical reactions 11

9)Obsrevations & Calculations

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10)Result 15

11)Conclusion 16

12)Bibiliography 17

AKNOWLEDGMENT

Firstly, I am extremely thankful to Mrs. Sheela Jose for helping me in my project. Secondly, I am thankful to my parents and my friends for their guidance.

CERTIFICATE

This is certified that this investigatory project has

been submitted by Dharmendra Kumar Yadav AISSCE No. as per the partial fulfillment of the All India Senior School Examination for the year 2010-2011.Examinition under my supervision, in the Chemistry Laboratory of Army School Shillong.

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CERTIFICATE

This is certified that this investigatory project has

been submitted by Sudipta Chakraborty AISSCE No. as per the partial fulfillment of the All India Senior School Examination for the year 2010-2011.Examinition under my supervision, in the Chemistry Laboratory of Army School Shillong.

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CERTIFICATE

This is certified that this investigatory project has

been submitted by Patrick Zolawma Lawlor AISSCE No. as per the partial fulfillment of the All India Senior School Examination for the year 2010-2011.Examinition under my supervision, in the Chemistry Laboratory of Army School Shillong.

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CERTIFICATE

This is certified that this investigatory project has

been submitted by Mithun Roka AISSCE No. as per the partial fulfillment of the All India Senior School Examination for the year 2010-2011.Examinition under my supervision, in the Chemistry Laboratory of Army School Shillong.

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CERTIFICATE

This is certified that this investigatory project has

been submitted by Pushpak Mehriwala AISSCE No. as per the partial fulfillment of the All India Senior School Examination for the year 2010-2011.Examinition under my supervision, in the Chemistry Laboratory of Army School Shillong.

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