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1. March 2016 Under The Guidance Of Department Of Chemistry (043) 2. Contents Acknowledgement Aim Of the project o Introduction o Theory o Requirements oChemical EquatIons oProcedure oPrecautIons oObservatIons oCalculatIons oResults o ConclusIons 3. ACKNOWLEDGEMENT Apart from my efforts, the success Of any project depends largely on the encouragement and guidelInes Of many others. I take this opportunity to express my gratitude to the people who have been Instrumental In the successful completion Of this project. I would like to show my greatest appreciation to our teacher .I can't say thank you enough for his tremendous support and help. I feel motivated and encouraged every time I attend his meetIng. Without his encouragement and guidance this project would not have materialized. The guidance and support received from all the members who contributed and who are contributIng to this project, was vital for the success Of the project. I am grateful for their constant support and help. Last but not least I wish to avail myself Of this opportunity, express a sense Of gratitude and love to my friends and my beloved parents for their manual support, strength, and help 4. AIM To study the PresenceOfOxalateIonsInGuava fruit at different stages Of ripenIng. uava is a common sweet fruit found InIndia 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 OfOxalateIons whose content varies durIng the different stages Of ripenIng. Guavas have a pronounced and typical fragrance, similar to lemon rInd but less In strength. What Is Oxalate? 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 OfOxalateIn our body. The Oxalate present In the body is excreted In the form Of urIne as waste. Too much OfOxalateIn our urIne results In a medical condition called hyperoxaluria, commonly referred to as kidney stones. Diet is looked upon as a preventive G I 5. measure In addition to medication to treat kidney stones. Theory xalate Ions are extracted from the fruit by boilIng pulp with dilute H2SO4. The OxalateIons 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. 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 phenolphthaleInIndicator. O T 6. Requirements (A) Apparatus 100 ml measurIng flask Pestle & Mortar Beaker Burette Funnel WeighIng machIne Filter Papers (B) Chemicals 7. March 2016 1. dil. H2SO4 2. (N/10) KMnO4 solution (C) Guava fruits at different stages Of ripenIng. Chemical EquatIons Molecular EquatIons Ionic EquatIons 8. Procedure (1) Weighed 50 g Of fresh Guava and crushed it to a fIne pulp usIng pestle and mortar. (2) Transferred the crushed pulp to a beaker and added about 50 ml dilute H2 SO4 to it. (3) Boiled the content for about 10 mInutes. Cooled and filtered the contents In a 100 ml measurIng flask. (4) Made up the volume 100 ml by addIng ample amount Of distilled water. (5) Took 20 ml Of the solution from the flask and added 20 ml Of dilute sulphuric acid to it. (6) Heated the mixture to about 600 C and titrated it agaInst (n/10) KMnO4 solution taken In a burette till the end poInt had an appearance Of pInk colour. (7) Repeated the above experiment with 50 g Of 1day, 2 day and 3 day old Guava fruits. PrecautIons 1. There should be no parallax while takIng measurements. 2. Spillage Of chemicals should be checked. 3.Avoid the use Of burette havIng a rubber tap as KMnO4 attacks rubber. 4.In order to get some idea about the temperature Of the solution touch the flask with the back side Of your hand. When it becomes unbearable to touch, the required temperature is reached. 9. 5.Add about an equal volume Of dil. H2 SO4 to the Guava extract to be titrated (say a full test tube) before addIng KMnO4 . 6.Read the upper meniscus while takIng burette readIng with KMnO4 solution. 7.In case, on addition Of KMnO4 a brown ppt. appears, this shows that either H2 SO4 has not been added or has been added InInsufficient amount. In such a case, throw away the solution and titrate agaIn. ObservatIons 1.Weight Of the Guava fruit for each time was 50 g. 2.Volume OfGuava extract taken for each titration was 20 ml. 3.Normality Of KMnO4 solution was (1/10). 4.END POInT: Colour Changes to pInk Guava Solution Burette readIng Initial FInal ReadIng Volume Of KMnO4 Concurrent ReadIng Raw 150 18 132 136.06 Semi- ripened 150 13 137 Ripened 150 10.8 139.2 10. 1) For raw Guava N1V1 = N2V2 ?N1 x 10 = (1/10) x132 ?1/10 x Normality OfOxalate = (x/100) = strength OfOxalateIn fresh Guava extract = normality x Eq. mass OfOxalate ion = 1.32/100 x 44g/litre Of diluted extract = 0.581 g L-1 2) For semi ripened Guava (1 day old). Strength OfOxalateIn one day old Guava extract = (1.37 /100) x 44g/litre Of diluted extract = 0.603 g L-1 3) For ripened Guava Strength OfOxalateIn fresh Guava extract = ( 1.39/100) x 44g/litre Of diluted extract = 0.612 g L-1 11. (a) The normality OfOxalateIonsOf; (i) Fresh Guava solution is = 1.32 ml (ii) Semi-ripen Guava solution is = 1.37 ml (iii) Ripened Guava solution is = 1.39 ml (b)The strength OfOxalateIonsOf; (i) Fresh Guava solution is = 0.58 ml (ii) Semi-ripened Guava is = 0.60 ml (iii) Ripened Guava is = 0.61 ml The content OfOxalateIonsInGuava was found to be 59.67 per cent, which is close to the literature value Of 60 percent. It was also noticed that the content Of oxalic Ions grows with ripenIng OfGuava.