chemistry project

Aim: To study the presence ofoxalate ions in guava fruit atdifferent stages ofripening.
Introduction: guava is a common sweet fruit found in India andmany other places around the world. Guavas Are plants in the Myrtle family (Myrtaceae) genusPsidium (meaning "pomegranate" in Latin), whichcontains about 100 species of tropical shrub. On ripeningit turns yellow in color. Rich in vitamin C, this fruit is a richsource of oxalate ions whose content varies during thedifferent stages of ripening.Guavas have a pronounced and typical fragrance, similar to lemon rind but less instrength.
What is oxalate: it is a carboxylic acid, primarily found in plants and animals. It is not an essentialmolecule and is excreted from our body, unchanged. Our body either producesoxalate on its own or converts other molecules like Vitamin C to oxalate. Externalsources like food also contribute to the accumulation of oxalate in our body. Theoxalate present in the body is excreted in theform of urine as waste. Too much of oxalatein our urine results in amedical condition calledhyperoxaluria, commonlyreferred to as kidneystones. Diet is looked upon as apreventive measure in addition to medication to treatkidney stones.

Theory: oxalate ions areextracted from thefruit by boiling pulpwith dilute H2SO4.The oxalate ions are estimatedvolumetrically, by titrating thesolution with KMnO4 solution.A reagent, called thetitrant, of a known concentration (a standard solution) andvolume is used to reactwith a solution of theanalyte ortitrand, whoseconcentration is notknown. Using a calibrated burette or chemistry pipetting syringe to add thetitrant, it is possible to determine the exact amount that has been consumedwhen the endpoint is reached. The endpoint is the point at which the titration iscomplete, as determined by an indicator. This is ideally the same volume as theequivalence point.he volume of added titrant at which the number of moles of titrant isequal to the number of moles ofanalyte, or some multiple thereof (asin polyprotic acids). In the classicstrong acid-strong base titration, theendpoint of a titration is the point at whichthe pH of the reactant is just about equal to7, and often when the solution takes on apersisting solid colour as in the pink of phenolphthalein indicator.