Class 12
Class 12
Class 12
Tvcnjuufe!cz!!
Name : .............................................
Vaibhav Kumar
12 A
Class : ....................
CONTENT
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Bjn!pg!uif!qspkfdu!!
Š Jouspevdujpo!
Jouspevdujpo!
Š Uifpsz!
Uifpsz!
Š Sfrvjsfnfout!
Sfrvjsfnfout!
Š Qspdfevsf!
Qspdfevsf!
Š Pctfswbujpot!
Pctfswbujpot!
Š Sftvmu!
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Š Cjcmjphsbiqz
!
Aim :
L To analyze the given samples of commercial antacids by determining the
amount of hydrochloric acid they can neutralize.
Introduction :
L 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.
L Some enzymes require mildly alkaline conditions while others operate only in
weakly acidic media. The enzymes control the digestion of proteins present
acid is secreted and it provides mildly acidic conditions required for the
lining the stomach, which are coupled to systems to increase acid production
when needed.
L 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
completely neutralize any gastric acid that passes further down into the
and secrete mucus. Mucus forms a viscous physical barrier to prevent gastric
L 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.
L To make sure that the pH of the stomach remains in a specific range, many
substances are added to the antacids.
Theory :
L Antacids react with excess stomach acid by neutralization.
HCl + NaOH → H2O + NaCl
L 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.
L 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.
L 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.
L Hydrochloric acid (HCl) and sulfuric acid (H2SO4) are common examples. In
water, these break apart into ions:
L Bases are proton acceptors which convert into conjugated acids. They are
generally substances which contain hydroxide ion (OH-) or produce it in
solution.
L 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)
NaOH→ -
(aq)+OH (aq)
L Burette(50ml)
L Pipette(20ml)
L Conical Flasks(250ml)
L Measuring Cylinder(10ml)
L Beakers(100ml)
L Standard Flasks(100ml)
L Filter Paper
L Funnel
L Bunsen Burner
L Weighing machine
L Glass Rod
L Water
L Crusher
b. Chemicals:
L NaOH powder
L Na2CO3 powder
L Phenolphthalein
L Methyl Orange
Procedure :
L Now, powder the four antacid samples and weigh 0.5 g of each.
L 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
L Add a few drops of phenolphthalein indicator and warm the flask over a
bunsen burner till most of the powder dissolves.
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Op/!
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1. 0 17 17
2. 18 35 17
N1 x 17 = 0.1 x 20
Normality of HCl, N1= 2/17 = 0.11 ≈ 0.1
Result :
L 1g of Eno Pineapple required 29 ml of Sodium Hydroxide (NaOH) to titrate it
completely.
L 1 g of Eno Lemon required 24 ml of Sodium Hydroxide (NaOH) solution to
titrate it completely.
L 1 g of Digene lime required 9 ml of Sodium Hydroxide (NaOH) to titrate it.
L 1 g of Omez required 24 ml of Sodium Hydroxide (NaOH) to titrate it
completely.
L 1 g of Pephyrous required 40 ml of Sodium Hydroxide (NaOH) to titrate it
completely.
L 1 g of Gelusil required 22 ml of Sodium Hydroxide (NaOH) to titrate it
completely.
L 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.