Presence of Oxalate ions inGuava A Chemistry Investigatory Project Aagam 21 th (science) This does not necessarily endorse or accept every statement made or opinion expressed or conclusion drawn. Kavita Kaur Mr. Shalini Dikshit (PGT Chemistry) (Principal) (K. but only signifies the acceptance of the project for the purpose it is submitted for.Vallabh Vihyanagar) .Certificate This is to certify that Aagam Mundhava of class 12th(science) has satisfactorily completed the project in chemistry on Presence of Oxalate ions prescribed by the CBSE course in the academic year 2014-15. Mrs.V. I have examined the project and hereby accord my approval of it as a study carried out and presented in the manner required for its acceptance. Contents o Aim of the project o Introduction o Theory o Requirements o Chemical Equations o Procedure o Observations o Calculations Conclusions o o Precautions o . which contains about 100 species of tropical shrub. The oxalate present in the body is excreted in the form of urine as waste. many Guavas have a pronounced and typical fragrance. this fruit is a rich source of oxalate ions whose content varies during the different stages of ripening. On ripening it turns yellow in color. Introduction G uava is a common sweet fruit found in India and other places around the world. O . similar to lemon rind but less in strength. External sources like food also contribute to the accumulation of oxalate in our body. Rich in vitamin C. It is not an essential moleculeand is excreted fromour body. What is oxalate? I t is a carboxylic acid. primarily found in plants and animals.AIM MM: To study the presence of oxalate ions in guava fruit at different stages of ripening. Diet is looked upon as a preventive measure in addition to medication to treat kidney stones. Guavas are plants in the Myrtle family (Myrtaceae) genus Psidium (meaning "pomegranate" in Latin). unchanged. Our body either produces oxalate on its own or converts other molecules like Vitamin C to oxalate. Too much of oxalate in our urine results in a medical condition called hyperoxaluria. commonly referred to as kidney stones. This is ideally the same volume as the equivalence point. and often when the solution takes on a persisting solid colour as in the pink of phenolphthalein indicator. by titrating the solution with KMnO4 solution. whose concentration is not known. the endpoint of a titration is the point at which the pH of the reactant is just about equal to 7. T he volume of added titrant at which the number of moles of titrant is equal to the number of moles of analyte. The endpoint is the point at which the titration is complete. called the titrant. of a known concentration (a standard solution) and volume is used to react with a solution of the analyte or titrand. In the classic strong acid-strong base titration. as determined by an indicator.Theory xalate ions are extracted from the fruit by boiling pulp with dilute H2SO4. The oxalate ions are estimated volumetrically. A reagent. it is possible to determine the exact amount that has been consumed when the endpoint is reached. Requirements (A) Apparatus . Using a calibrated burette or chemistry pipetting syringe to add the titrant. or some multiple thereof (as in polyprotic acids). 100 ml measuring flask Funnel Pestle & Mortar Beaker Weighingmachine Burette Filter Papers (B) Chemicals 1. Chemical Equations 2. dil. H2SO4 (C) Guava fruits at different stages of ripening. (N/10) KMnO4 solution . Molecular Equations 2KMnO4+ 3H2SO4 HOOC-COOH.2H2O + [O] K2SO4+ 2MnSO4+2H2O + 4[O] 600C – 700C 2CO2+ 2H2O x 5 3KMnO4+ 3H2SO4+5 HOOC-COOH.2H2O 10CO2 K2SO4+ 2MnSO4+ 18H2O + Ionic Equations MnO4-+16H++ 5eC2O4 Mn2++ 4H2O x 2 2CO2+ 2e-x 5 2MnO4-+ 16H++ 5C2O42- 2Mn2++8H2O + 10CO2 . (2)Transfer the crushed pulp to a beaker and added about 50 ml dilute H2SO4 to it. 2 day and 3 day old guava fruits. Normality of KMnO4 solution was (1/10). (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.Procedure (1)Weighed 50 g of fresh guava and crushed it to a fine pulp using pestle and mortar. (4)Made up the volume 100 ml by adding ample amount of distilled water. Semiripened Ripened 3 Burette reading Initial 150 Final Volume Concurrent Reading of Reading KMnO4 18 132 150 13 137 150 10. 3. 4. Sr No. (7) Repeated the above experiment with 50 g of 1day. Weight of the guava fruit for each time was 50 g. Raw 2. Observations 1.2 Calculations 136. Volume of guava extract taken for each titration was 20 ml. (5)Took 20 ml of the solution from the flask and added 20 ml of dilute sulphuric acid to it. Cooled and filtered the contents in a 100 ml measuring flask.8 139.06 . END POINT: Colour Changes to pink Guava Solution 1. 2. (3)Boiled the content for about 10 minutes. guava extract = normality x Eq.1) For raw guava: N1V1 = N2V2 N1 x 10 = (1/10) x132 1/10 x Normality of oxalate = (x/100) = strength of oxalate in fresh .32 ml (ii) Semi-ripen guava solution is = 1.37 ml (iii) Ripened guava solution is = 1.32/100 x 44g/litre of diluted extract =0.581g L-1 2) For semi ripened guava (1 day old): Strength of oxalate in one day old guava extract = (1.603g L-1 3) For ripened guava: Strength of oxalate in fresh guava extract = ( 1.37 /100) x 44g/litre of diluted extract =0. (i) Fresh guava solution is = 1. (i) Fresh guava solution is =0.58ml .612g L-1 Results (a) The normality of oxalate ions of. mass of oxalate ion = 1.39/100) x 44g/litre of diluted extract = 0.39ml (b) The strength of oxalate ions of. 7. on addition of KMnO4a brown ppt.67 per cent. 4. Read the upper meniscus while taking burette reading withKMnO4 solution. There should be no parallax while taking measurements. the required temperature is reached.60 ml (iii) Ripened guava is = 0. 2. In such a case. Spillage of chemicals should be checked.61 ml Conclusions The content of oxalate ions in guava was found to be 59. Avoid the use of burette having a rubber tap as KMnO4attacksrubber. 3. When it becomes unbearable totouch. 6. Precautions 1. throw away the solutionand titrate again. 5. It was also noticed that the content of oxalic ions grows with ripening of guava. In case. appears. H2SO4to the guava extract tobe titrated (say a full test tube) before adding KMnO4. Add about an equal volume of dil. Bibliography .(ii)Semi-ripened guava is =0. In order to get some idea about the temperature of the solution touchthe flask with the back side of your hand. which is close to the literature value of 60 percent. this showsthat either H2SO4has not been added or has been added ininsufficient amount. Practical Chemistry by Laxmi Publications.com 2.google. The Family Encyclopedia by Dorling Kindersley.1.com www.com www. . Search engines used: www.google. 3.wikipedia.quora.google.com www.labs.com www.reader.
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