Oxalate Ions in Guava Chemistry Investigatory Project
Oxalate Ions in Guava Chemistry Investigatory Project
Oxalate Ions in Guava Chemistry Investigatory Project
G
uava is a common sweet fruit found in India
and many other places around the world.
Guavas are plants in the Myrtle family
(Myrtaceae) genus Psidium (meaning
"pomegranate" in Latin), which contains about 100
species of tropical shrub. On ripening it turns yellow in
color. Rich in vitamin C, this fruit is a rich source of oxalate ions
whose content varies during the different stages of ripening.
Guavas have a pronounced and typical fragrance, similar to lemon rind but less in
strength.
I
t is a carboxylic acid, primarily found in plants and animals. It is not an essential
molecule and is excreted from our body, unchanged. Our body either produces
oxalate on its own or converts other molecules like Vitamin C to oxalate. External
sources like food also contribute to the accumulation of oxalate in our body. The
oxalate present in the body is excreted in the
form of urine as waste. Too much of oxalate
in our urine results in a
medical condition called
hyperoxaluria, commonly
referred to as kidney
stones. Diet is looked upon as a
preventive measure in addition to medication to treat
kidney stones.
O
xalate ions are
extracted from the
fruit by boiling pulp
with dilute H2SO4.
The oxalate ions are estimated
volumetrically, by titrating the
solution with KMnO4 solution.
A reagent, called the titrant, of a known concentration (a standard solution) and
volume is used to react
with a solution of the analyte or
titrand, whose
concentration is not
known. Using a calibrated burette or chemistry pipetting syringe to add the
titrant, it is possible to determine the exact amount that has been consumed
when the endpoint is reached. The endpoint is the point at which the titration is
complete, as determined by an indicator. This is ideally the same volume as the
equivalence point.
T
he volume of added titrant at which the number of moles of titrant is
equal to the number of moles of
analyte, or some multiple thereof (as
in polyprotic acids). In the classic
strong acid-strong base titration, the
endpoint of a titration is the point at which
the pH of the reactant is just about equal to
7, and often when the solution takes on a
persisting solid colour as in the pink of phenolphthalein indicator.
(A)
100 ml measuring flask Pestle & Mortar Beaker Burette
(B) Chemicals
1. dil. H2SO4 2. (N/10)
KMnO4
solution