Comparative study

Of commercial
Antacids…

Chemistry Investigatory Project

Submitted by
Name : .............................................
Class : ....................
 CERTIFICATE

This is to certify that .........................................................................,

Reg. No. ............................ of class XII of GREEN PARK

INTERNATIONAL SENIOR SECONDARY SCHOOL has

successfully completed his / her project report in chemistry on the topic

“ Comparitive study of commercial antacids....” for the

partial fulfillment of AISSCE as prescribed by the CBSE in the year

2018 - 2019.

Viva voce held on :

Registration No :

Signature of the Guide Signature of the principal

Signature of the Internal Signature of the External

Examiner Examiner
 ACKNOWLEDGEMENT

At the outset, I express our gratitude to the Almighty Lord

for the divine guidance and wisdom showered on me to

undertake this project.

I am immensely grateful to my beloved Principal for her

involvement in this project by providing useful inputs and timely

suggestions.

I am also thankful to my Chemistry teacher for her

guidance and help to make this project a success.

My Parents also played a key role in shaping up this project

nicely and I convey my special thanks to them as well.

CONTENT

 Aim of the project

 Introduction

 Theory

 Requirements

 Procedure

 Observations

 Result

 Bibliography
Aim :
To analyze the given samples of commercial antacids by determining the amount of

hydrochloric acid they can neutralize.

Introdcton : :
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. The enzymes 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.
Theory :
 Antacids react with excess stomach acid by neutralization.

HCl + NaOH  H2O + NaCl

 During the process, hydrogen ions H+ from the acid (proton donor) or a
hydronium ion H3O+ and hydroxide ions OH- 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) + Cl- (aq)

(OR)
H2SO4  H+ (aq) + HSO4 -(aq)

 Bases are proton acceptors which convert into conjugated acids. They are
generally substances which contain hydroxide ion (OH-) 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)+OH-(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.
Requirements :
a. Apparatus:

 Burette(50ml)

 Pipette(20ml)

 Conical Flasks(250ml)

 Measuring Cylinder(10ml)

 Beakers(100ml)

 Standard Flasks(100ml)

 Filter Paper

 Funnel

 Bunsen Burner

 Weighing machine

 Clean & glazedwhite tile

 Glass Rod

 Water

 Crusher

b. Chemicals:

 NaOH powder

 Na2CO3 powder

 10M conc. HCl acid

 Four different brands of antacids

 Phenolphthalein

 Methyl Orange
Procedure :
 First prepare 1 litre of approximately N/10 solution of HCl by diluting 10ml of

the given 10M HCl acid to 1litre.

 Next prepare1litre of approx.N/10NaOH solution by dissolving 4.0g of NaOH to

make1litre of solution.

 Similarly prepare N/10 Na2CO3 solution by weighing exactly 1.325g of

anhydrous Na2CO3 and then dissolving it in water to prepare exactly 0.25L or 250

ml of Na2CO3 solution.

 Now, standardize the HCl solution by titrating it against the standard Na2CO3

solution using methyl orange as indicator.

 Similarly standardize the NaOH solution by titrating it against standardized HCl

solution using phenolophtahlein as indicator. Stop the titration when the pink

colour of the solution disappears.

 Now, powder the four antacid samples and weigh 0.5 g of each.

 Add 25 ml of the standardised HCl to each of the weighed samples taken in

conical flasks. Make sure that the acid is in slight excess so that it neutralize all

the basic character of the tablet powder.

 Add a few drops of phenolphthalein indicator and warm the flask over a

bunsen burner till most of the powder dissolves.

 Filter the insoluble material.

 Titrate this solution against the standardized NaOH solution till a permanent

pinkish tinge is obtained.

 Repeat the same experiment for all other samples too.

 Observations :
Standardisation of HCl solution:

Volume of 0.1N Na2CO3 taken is 20 ml

Indicator used is Methyl Orange

Serial Burette readings Volume of acid

No. used (ml)
Initial reading Final reading
1. 0 17 17
2. 18 35 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 is 20.0 ml

Indicator used is Phenolphthalein
Serial Burette readings Volume of acid
No. Initial reading Final reading used (ml)
1. 0 16 16
2. 17 33 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 for titration = 20 ml

 Antacid Volume of (NaOH) used for
Neutralizing unused (HCI)
1. Eno pineapple 29
2. Eno Lemon 24
3. Digene Lime 9
4. Omez 24
5. Pephyrous 40
6. Gelusil 22

Result :
 1g of Eno Pineapple required 29 ml of Sodium Hydroxide (NaOH) to titrate
it completely.
 1g of Eno Lemon required 24 ml of Sodium Hydroxide (NaOH) solution
to titrate it completely.
 1g of Digene lime required 9 ml of Sodium Hydroxide (NaOH) to titrate it.
 1g of Omez required 24 ml of Sodium Hydroxide (NaOH) to titrate it
completely.
 1g of Pephyrous required 40 ml of Sodium Hydroxide (NaOH) to
titrate it completely.
 1g 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.
 BIBLIOGRAPHY

 http://www.reachoutmichigan.org/funexperiments/quick/csustan/ antacid

 http://ien2.uneche.maine.edu/genchemlabs/Antacid /antacid2.htm
 http://www.chem.latech.edu/~deddy/chem104/104
Antacid.htm

 http://www.images.google.com

 http://www.wikipedia.com