To Study the presence of Oxalate Iron in Gauava

STUDY OF OXALATE ION CONTENT IN GUAVA FRUIT….                                                                       


To study the presence of oxalate ion content in guava fruit at different stages of ripening.


Guava is sweet, juicy and light or dark green colored fruit. It is cultivated in all parts of India. When ripe it acquires yellow color and has a penetrating strong scent. The fruit is rich in vitamin C and minerals. It is a rich source of oxalate and its content in the fruit varies during different stages of ripening.

Besides its unique flavor and fragrance, guava has been hailed as one of the super fruits due to the numerous health benefits it offers. It indeed is a powerhouse of nutrients. This humble fruit is extraordinarily rich in vitamin C, lycopene and antioxidants that are beneficial for skin. Guavas are also rich in manganese which helps the body to absorb other key nutrients from the food that we eat. Guavas contain folate, a mineral which helps promote fertility. The potassium in guavas helps normalize blood pressure as well. Since it contains about 80% of water it helps keep our skin hydrated.


As one guava has a high content of vitamin C, one guava fruit contains 4 times more vitamin C than an average size orange and 10 times more vitamin A than a lemon.

It also contains vitamin B2, E and K, fiber, calcium, copper, folate, iron, manganese, phosphorous and potassium. With all the nutrition that it provides, guava hardly contains any fats. Moreover, it is one of the least chemically treated and sprayed fruits.

Some of the wider applications, guava is related to health. They are:


 Vitamin C present in guava helps improve immunity and protects us against common infections and pathogens


Lycopene, quercetin, vitamin C and other polyphenols act as potent antioxidants which neutralize free radicals generated in the body, preventing the growth of the cancer cells.


Due to rich fibre content and low glycaemic index, guavas prevent the development of diabetes. While the low glycaemic index inhibits a sudden spike in sugar levels, the fibre content   ensures the sugar levels are well regulated


Guavas improve the sodium and potassium balance of the body, thereby regulating blood pressure in patients with hypertension. Guavas also help lower the levels of triglycerides and bad cholesterol (LDL), which contribute to the development of heart disease.


Guavas are rich in vitamin A, vitamin C and antioxidants like carotene and lycopene which help protect the skin from wrinkles. A guava a day, keeps fine lines away.


Guavas contain vitamin B3 and vitamin B6, also known as niacin and pyridoxine respectively, which help in improving blood circulation to the brain, stimulating cognitive function and relaxing the nerves.

Thus there are several aspects in which guava is helpful in maintaining our physical and mental health.


To study the presence of oxalate ion content in guava fruit at different stages of ripening.


100ml measuring flask, pestle and mortar, titration flask, funnel, burette, weight-box, pipette, filter paper, dilute H₂SO₄, N/20KMnO₄ solution and guava fruits at different stages of ripening.


Oxalate ions are extracted from the fruit by boiling pulp with dil. H₂SO₄. Then oxalate ions are estimated volumetrically by titrating the solution with standard KMnO₄ solution


  1. Weigh 50.0 g of fresh guava and crush it to a fine pulp using pestle-mortar.
  2. Transfer the crushed pulp to a beaker and add about 50 ml dil. H₂SO₄ to it. Boil the contents for about 10 minutes.
  3. Cool and filter the contents in a 100 ml measuring flask. Make the volume up to 100 ml by adding distilled water.
  4. Take 20 ml of the solution from the measuring flask into a titrating flask and add 20 ml of dilute sulphuric acid to it. Heat the mixture to about 60ᵒC and titrate it against N/20 KMnO₄ solution taken in a burette. The end point is appearance of permanent light-pink color.
  5. Repeat the above experiment with 50.0 g of 1, 2 and 3 days old guava fruit.



  1. Weight of guava fruit taken each time = 50.0 g
  2. Volume of guava extract taken in each titration = 20. 0 ml
  3. Normality of KMnO₄ solution = 1/20

Guava extract from

    Burette readings Concordant volume of N/20 KMnO solution used
  Initial     Final
Fresh guava
One day old guava
Two days old guava
Three days old guava


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