Preparation of Sodium Carbonate

2. Preparation Of 1 M Na2CO3

Molecular mass of Na2CO3 = 106g
Mass of salt in 100 ml of 1M solution = 10.6g

Weighing of salt using electrical balance

* Mass of Na2CO3 + beaker = 78.64g * Mass of beaker = 68.04g * Mass of Na2CO3 = 10.6g

1. 10.6g of Na2CO3 was weighed in a dry beaker. Small amount of distilled water was added and the salt was dissolved. 2. The contents of the beaker were transferred to clean volumetric flask of 100ml. 3. Collection of washings was done 3-4 times. 4. The solution was made 100ml. Shook well to ensure the uniformity of the solution. 5. The contents were transferred to the storing bottle and it was labeled 1M Na2CO3 solution.

3. Preparatiion of 1 M NaHCO3 solution

Molecular mass of NaHCO3 = 79.64g Mass of beaker = 71.24g Mass of NaHCO3 = 8.40g

1. 8.4g of NaHCO3 was weighed in a dry beaker. Small amount of distilled water was added and the salt was dissoleved. 2. The contents of the beaker were transferred to a clean volumetric flask of 100 ml. 3. Collection of washings was done 3-5 times. 4. The solution was made 100ml. Shook well to ensure the uniformity of the solution. 5. The contents wee transferred to storing bottle and it was laveled 1 M NaHCO3 solution.

4. Preparation of 0.1 M Na2S2O3. 5H2O

Solution

Molecular mass of Na2S2O3.5H2O = 248g
Mass of salt in 250ml of 0.1 M solution = 6.2g

Weighing of salt using electronic balance

Mass of Na2S2O3. 5H2O + beaker = 70.60g Mass of beaker = 64.36g Mass of Na2S2O3. 5H2O = 6.24g

1. 6.2g of Na2S2O3. 5H2O was weighed in a dry beaker. Small amount of distilled water was added and the salt was dissolved.

2. HH

3. The contents of the beaker were transferred to a clean volumetric flask 250ml.

4. Collection of washings was done 3-4 times.

5. The solution was made 250ml. Shook well, to ensure uniformity of the solution.

6. The contents were transferred to the strain bottle and it was labeled 0.1 M Na2S2O3. 5H2O solutions.

Preparation of 2.5% concentrate of H2SO4

a. H i. A clean 250ml measuring cylinder was taken and distilled water was poured till 50ml mark. ii. A 100ml measuring cylinder was taken and dried thoroughly. This cylinder should be absolutely dry. iii. 50ml of concentrate H2SO4 was measured. iv. This was poured in the previous measuring cylinder containing water, 5-6 drop at a time. v. This was accompanied by constant stirring and the cylinder was left time-to-time to cool. vi. This was repeated till the last drop of H2SO4 was transferred. vii. Another 20ml of water is poured in the cylinder so as to transfer the deposits of concentrate H2SO4 on the walls. viii. More water is added to make the volume up to 200ml ix. Solution is transferred to a storing bottle and labeled 25% concentrate H2SO4 and placed away from local throughway.

Preparation of indicator for titration

1. Half horn spatula of starch was taken in a test tube and excess of distilled water was added to it and shaken well.

2. 100ml of distilled water was boiled in 150ml beaker and starch solution was added drop by drop with constant stirring to make a colorless clear solution.

3. The solution is boiled for 3-4 minutes more. 4. Solution is cooled slowly and transferred to a storing bottle labeled starch indicator.

Preparation for honey solution 1. 2ml of honey was measured in a graduated pipette least count = 0.05ml 2. 2-3 ml of distilled water was added to it and it was shaken till a clear solution was obtained. 3. This clear solution was transferred to a 50ml measuring cylinder . 4. This washings were collected 3-4 times. 5. The solution was made 50 ml and shook well. 6. The solution was transferred to storing bottle and was labeled as sample 1. 7. Repeat the above steps for the other sample.

CORE PROCEDURE 1. 1.An iodometric flask was cleaned using the soap solution, then with the tap water followed by distilled water.

2. 2.10 ml of honey solution was pipetted out into it with the help of a graduated pipette.

3. 20ml each of NaHCo3 and Na2CO3 was poured into it using a measuring cylinder

4. 50ml of 12 solution was added to the iodimetric flask and shaken well.

5. The flask was labeled with the name of the honey and was immediately placed in the dark.

6. The above steps were repeated for other honey samples and were left for 1 and a half hour.

7. After one and a half hour, shook the iodometric flask and pipetted 10ml of 25% concentrate H2SO4 using a measuring cylinder.

8. 1ml of starch indicator were also added to it and titrated against Na2S2O3.5H2O solution in the conical flask a measuring cylinder.

9. 1ml of starch indicator were also added to it and titrated against Na2S2O3.5H2O solution taken in the burette.

10. The same was repeated for the other honey samples.

PROCEDURE FOR CARRYING OUT TITRATION

1. All apparatus i.e. beakers, conical flasks, burette, pipette etc. were first cleaned with soap solution, then by tap water followed by distilled water to remove all the tap water. 2. A burette was rinsed with Na2HHHhhhjjjjjggggS2O3.5H2O solution and the pipette was rinsed with honey iodine solution. 3. The burette was filled with the Na2S2O3.5H2O solution and fixed to theclamp stand and made sure that no air bubbles were present in the nozzle. 4. 10ml of honey iodine solution was pipetted out in a clean conical flask using a graduated pipette. 5. 10ml of 25% concentrate H2SO4 was measured using a measuring cylinder and added to the conical flask. Shook well. 6. Then it was titrated against thiosulphate solution taken in the burette tgill solution turned light yellow. Then added starch indicator. Added the thiosulphate solution drop by drop near the end point. At the end point the colour of the solution changes from violet to colorless. 7. The above steps were repeated to get three concurrent readings. 8. The above steps were repeated for the other sample of honey.

Observations & calculations Deriving the general formula

* Molarity of I2 solution is 0.095 M * In 1000 ml : no of moles of I2=0.095 * In 50 ml : no of moles of I2 = 0.095*50/1000=0.0048

2 S203 2- +I2 == S4O6 2- +2I- 2 : 1

M1 * V1/ N1 =M2*V2 / N2

* M1 : Molarity of thiosulphate solution = 0.10 M * V1 : Volume of thiosulphate solution = V1 * N1 : Number of moles =2 * M2 : Molarity of dextrose = M2 * V2 : Volume of honey iodine solution = 10 ml * N2 : Number of moles = 1

0.10* V1 /2 = M2 *10 /1
M2=0.005*V1

Now * 1000 ml solution contains = 0.005*V1 moles * 1 ml solution contains = 0.005*V1/1000 moles * 100 ml solution contains = 0.005 * V1 *100/1000 moles

= 0.0005 * V1 moles
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