ALL INDIA SENIOR

SECONDARY SCHOOL

Topic –

To study the presence of oxalate ion in guava .

Submitted by -

Shashank mishra

xiith

CertificateIt is to certify that Shashank has satisfactorily completed the project in Chemistry on “Oxalate ion” prescribed by AISSEE course in this school in the year – 2012-13

Chemistry teacher,s sign –

Principal,s sign –

AcknowledgementI full great pleasure to submit this Project .

My subject teacher and my friend

helped me a lot in this project .

I am thankful to all of them .

Made by –

Shashank Mishra

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

TheoryOxalate ions are extralid from the fruit by boiling pulp with dil. H2SO4 .

The oxalate ions are estimated volumetrically by titrating the solution with standard KMnO4 solution .

Nutrition value of Guava –Calcium – 50 mg

Carbohydrate -19.6 gm

Fibre – 8.9 gm

Niacin – 2 mg

Phosphorus – 48mg

Protein – 1.35gm

Total Fat – 0.9 gm

Vitmin A – 412 mg

Vitmin B – 1.115mg

Vitmin c – 495 mg

Requirements Appratus –100 ml measuring flask , pestle , mortar , beaker , titration flask , funnel , burette , weight box , filter

paper .

Chemicals –

Dilute H2SO4 , N/20 KMnO4 solution , guava fruit at different stages of ripining .

Procedure1. Weigh 50.00gm of fresh guava & crush it to a fine

pulp using pesthe & mortar .2. Transfer the crushed pulp to a beaker and add

about 50 ml dil. H2SO4 to it .3. Boil the contents for about 10 min.4. Cool & filter the contents in a 100 ml measuring

flask. Make the volume upto 100 ml by adding distilled water .

5. Take 20 ml of the solution from the measuring flask into a titration flask and add 20 ml of dil. Sulphuric acid to it .

6. Heat the mixture to about 600c & titrate it against N/20 KMnO4 solution taken in a burette . The end point is appearance of permanent light pink colour.

7. Repeat the above experiment with 50.00 gm of 1,2,3 days old guava fruit .

Observations –1. Weight of guava fruit taken each time =

50gm2. Volume of guava extract taken in each

titration = 20 ml .3. Normality of KMnO4 solution = 1/20 .

Table for Raw Guava -

Guava solution

(ml)

Buritte reading Initial(ml) final(ml)

Conc. Reading

(ml)

20

20

20

Semi riped guava –Fully riped guava –

Result - Oxalate ions present more in riped guava