EXPERIMENT 20

I. Identity

a. Title :Determination of iron ion concentration in Sangobion by permanganometric titration.b. Objective : To determine concentration of iron ion in Sangobion by permanganometric c.Day/Date:Monday, 13th May 2011

d. Department/Faculty:Chemistry education department/ Mathematic and Sciences

e.Names of group:

II. Background

Theorytical

Iron is one mineral that is needed by the body. In the human body there are approximately 3.5 to 4.5 grams of iron, in which two thirds are found in the blood, while the rest are found in the liver, bone marrow, and muscle. It is role in the production of red blood cells are very famous. The recommended amount of iron per day is 18 mcg. Iron is useful to help the formation of hemoglobin in red blood cells and prevents of anemia.

Red blood cells are containing a protein called hemoglobin, and each has one atom of hemoglobin iron. This is the iron in hemoglobin that binds oxygen in the blood in the lungs to be distributed throughout the body. After removing oxygen, hemoglobin is binding of carbon dioxide (CO2) to be secreted by the lungs.Function

1. Iron has a role in the process of cell respiration, namely as a cofactor for the enzyme involved in the oxidation reduction reaction.2. Energy metabolism, in each cell, iron work with electron transport chain proteins that has a role in the final step of energy metabolism. A total of more than 80% iron in the body is in hemoglobin.ImpactDisadvantagesThe reduced work ability, lack of energy in general causes pale, weakness, fatigue, dizziness, loss of appetite, reduced fitness, immunity and impaired wound healing, and the ability to regulate body temperature decreased, and difficulty breathing (gasping breath), a beating heart faster, fatigue, difficulty concentrating, can not sleep well, pain during menstruation, the tip of chapped lips, eye irritation, and even hair loss.

Livron B Plex and supra livron are the food supplements that contain iron. Iron contained in Livron B Plex and supra livron are the form of ferrous gluconate (C12H24FeO14). To examine the content of Fe2 +, then the experiment was conducted using the titration permanganometri.Ferrous gluconateDasabion is also one of the food supplements that contain iron. Iron contained in dasabion is the form of iron (II) fumarat (C12H24FeO14). To examine the content of Fe2 +, then the experiment was conducted using the titration permanganometri.

Iron (II) Fumarat

Permanganometri titration is oxidationmetric titration using standard solution of potassium permanganate (KMnO4). In the redox reaction of KMnO4 as an oxidator will occur a reduction reaction. One drop of 0.1 N permanganate gives a clear pink color on the volume of solution which is used in a titration. This color is used to indicate the excess reagent. Permanganate undergoes various chemical reactions because manganese can be present with oxidation number +2, +3, +4, +6, +7. Its ability to capture the electron is determined by the acidity of the solution ion-MnO4. Reduction reactions experienced by ion MnO4 are as follows-

MnO4-(aq) + 8H+ (aq) + 5e Mn2+(aq) + 4H2O(l)

Permanganate reacts rapidly with many reducing agents based on the reaction, but some substances require heating or the use of a catalyst to accelerate the reaction. Permanganate is an oxidizing agent element that is strong enough to oxidize Mn (II) to MnO2 in accordance with the equation3Mn2+(aq) + 2MnO4-(aq) + 2H2O(l) 5 MnO2(s) + 4H+(aq)

Little excess of permanganate is present at the titration end point is sufficient to result in the precipitation of MnO2. However, given the slow reaction, MnO2 not normally precipitated at the end point of the titration of permanganate.

Permanganate solutions are unstable acidic because the permanganate acid decomposes according to the equation:

MnO4-(aq) + 4H+ (aq) + 5e MnO2(s) + 2H2O(l)

MnO4-(aq) + 2H2O(aq) + 3e MnO2(s) + OH-(aq)

From the equation above can be seen that KMnO4 most powerful oxidizing properties occur in a very sour mood. For the reduction reaction of KMnO4, Mn2+ is necessary to prevent the formation of the intermediate results in the form of a brown MnO2 by titration in hot conditions.

Aquades used to dissolve the solid KMnO4 must certainly have been free from organic substances capable of reducing KMnO4. To prevent this, a solution of KMnO4 boils it first. Furthermore, after the cold it is filtered using a glasswol filter or sinterglas. To avoid KMnO4 decompose by air, this solution is stored in dark bottles.

As a secondary standard solution, before being used to standardize a reducing, KMnO4 will be standardized with primary standard solution. Primary standard solution is a reducing agent, such as sodium oxalate (Na2C2O4). This reaction was slow at room temperature, so the solution is usually heated to around 60-70oC. Even at higher temperatures the reaction started slowly, but speed increases when the ion manganese (II) is formed. Manganese (II) acted as a catalyst and the reaction is called autocatalytic gripped, because the catalyst is produced in the reaction itself. Ions can provide catalytic effect in a way to react quickly with permanganate to form manganese oxidation conditioned medium (+3, +4), whereas in turn rapidly oxidizes oxalate ion to the divalent state. Standardized potassium permanganate can be used to determine the concentration of reducing agent, such as ferrous ions. Redox reactions that occur are as follows:

2 MnO4-(aq) + 16H+ + 5C2O4 (aq) 2 Mn2+(aq) + 8H2O(l) + 10CO2(g) MnO4-(aq) + 8H+ + 5Fe2+(aq) Mn2+(aq) + 5Fe3+(aq) + 4H2O(l)

Based on the redox reaction is occurred, then the indicator will show that the equivalent point has been achieved, indicated by the color change from transparent solution became purple. This change occurs when KMnO4 is used as titrant (Selamat and Lanang, 2004).III. Experiment Methods

Chemical Apparatus

ApparatusNumber

Measuring flask 250mL

Volumetric Pipette 10mL Analytical balance

Erlenmeyer flask 100mL

Erlenmeyer flask 250mL

Burette

Beaker glass 500mL

Beaker glass 100mL

Small funnel

Drop pipette

Statif and clem

Watch glass

Spatula

Erlenmeyer flask 250mL

Heater

Petri disk1 unit

1 unit

1 unit

1 unit

3 unit

1 unit1 unit

1 unit1 unit

2 units

1 set

2 units

2 units

3 units

1 unit

Materials

MaterialsAmount

Na2C2O4 (s) KmnO4 p.a

Aquades

C12H24Fe O14 C4H2FeO4 H2SO4 1N1,675 gram

0,813 gram

Enough

gram

10 mL

Procedures

1. 0.790 gram of KMnO4 was weighting and was entered into the beaker glass 500 mL.2. It was added by 250 mL of aquades and was stirred until it was dissolved completely. The solution was boiled in 10 minute in closed condition (beaker glass was closed by using watch glass).3. After cooled, it was filtered by using funnel in glasswol. The filtrate that got was saving in dark bottle (brown).4. Sodium oxalate was dried in oven in temperature is 1100C in 1-2 hours and was cooled in decicator until room temperature.5. Aquades 50mL was poured into measuring flask. Sodium oxalate was weighting 1.675 gram and was entered into the measuring flask 250mL. It was added by aquades until the volume is 250mL.6. 25mL of Na2C2O4 solution was entered into the measuring flask and was added by 3mL of H2SO4 1 N. The solution was heated until the temperature was 700C.7. The solution was titrated by KmnO4 solution until the color of solution is pale purple (still purple in 30 second).8. In this titration, the shaken was done completely.9. The volume of titrant that was used was noted and was repeated in three times.10. 25mL of Fe2+ salt solution (0.1N) was poured into Erlenmeyer 250 mL and was added by 3mL of H2SO4 1N.11. The solution was heated until the temperature is 700C. It was titrated by KMnO4 solution until the color of solution is pale purple (still purple in 30 second).

12. The volume of titrant that was used was noted and was repeat in three times13. The concentration of Fe2+ was determined.

IV. Experiment Results and Discussion

Experiment Results

No Procedures Experiment Results

10.79 gram of KMnO4 was weighting and was entered into the beaker glass 500mL[KMnO4] = 0,1 N = 0,02 M (because n = 5)

Mr KMnO4 = 158

mass = mol x Mr

=0,02 M x 0,25 L x 158

= 0,790 gramKMnO4 like crystal has dark violet color. The mass of KMnO4 is 0,790 gram

Picture 03. KMnO4 crystal

2250 mL of aquades was added and the solid of KMnO4 was stir until all of the solid of KMnO4 is dissolved. In close condition that solution take place in wacth glass was heated for 10 minutes0.790 gram of KMnO4 is dissolved into 250 mL aquades produce violet solution

Picture 04. KMnO4 solution

3Filtering that solution after cool by using funnel and its glaswol. The filtrat that get was save in the bottle.Filtrate that violet color is produced and there is little precipitate on filtering paperPicture 05. Little precipitate

4Sodium oxalate was dried in oven in temperature is 1100C in 1-2 hours and was cooled in decicator until room temperature.Na2S2O4 is white powderPicture 06. Na2S2O4 powder

5Aquades 50mL was poured into measuring flask. Sodium oxalate was weighting 1.675 gram and was entered into the measuring flask 250mL. It was added by aquades until the volume is 250mL

[Na2C2O4] = 0,1 N = 0,05 M (because the amount of electon thats released is 2) follow by equation below:C2O42-(aq) 2CO2(g) + 2e

Mr Na2C2O4 = 134

Massa = Mol x Massa molar

= M. Na2C2O4 x V. Na2C2O4 x Mr. Na2C2O4

= 0,05 M x 0,25 L x 134 gram/mol

= 1,675 gramNa2C2O4 0.1 N- [Na2C2O4] = 0,1 N = 0,05 M N= M x n

M = 0.1/2

=0.05 M- Mol Na2C2O4 = 250 x 0.05= 1.25 x 10-2 molPicture 07. Na2S2O4 powder

625mL of Na2C2O4 solution was entered into the measuring flask and was added by 3mL of H2SO4 1 N. The solution was heated until the temperature was 700C.Na2C2O4 is colorless solutionPicture 08. Na2S2O4 solution

7The solution was titrated by KMnO4 solution until the color of solution is pale purple (still purple in 30 second).In this titration, the shaken was done completely.KMnO4 solution is violet color. Titration was stopped until the solution become pink.When titration can be used stirer. This has purpose that shacked done. It was used magnetic stirred.

Pictures 09. KMnO4 Standardization

9The volume of titrant that was used is noted and titration was repeated in three times. In this titration the volume of titrate that was used is 25.00mL.

Titration

Volume (mL)I

24.45II

24.48III

24.52average

24.48M equivalent C2O42-= N x V= 0.1 x 25.00= 2.5 m equiv.M equivalent C2O4 2-= M equivalent MnO4-

Meqiv = N MnO4- x V MnO4-

Meqiv = N MnO4- x 24.48N MnO4- = 0.102 N

10Livron B Plex

25mL of Fe2+ salt solution (0.1N) was poured into erlenmeyer 250mL and was added by 3mL of H2SO4 1N.Dasabion25mL of Fe2+ salt solution (0.1N) was poured into erlenmeyer 250mL and was added by 3mL of H2SO4 1N

N Fe2+= 0.1 N , V Fe2+= 100 mL= 0.1 LN Fe2+= M.n

0.1 = 1 (( gr/Mr)/(1000/100))

Gram Fe 2+= (0.1 x 169.901x 100 mL) = 1.69 gram

So, to make 100 mL of Fe 2+ solution must dissolved 1.69 gram of Livron B plex is equal with 9 capsule.N Fe2+= 0.1 N , V Fe2+= 100 mL= 0.1 L

N Fe2+= M.n

0.1 = 1 (( gr/Mr)/(1000/100))

Gram Fe 2+= (0.1 x 448.156x 100 mL) = 4.5 gram

So, to make 100 mL of Fe 2+ solution must dissolved 4.5 gram of dasabion is equal with 9 capsule.

11The solution was heated until the temperature is 700C. It was titrated by KMnO4 solution until the color of solution is pale purple (still purple in 30 second).The color of solution is

12The volume of titrant that was used is noted and titration was repeated in three times. Volume of titrate is 25.00mL.

Livron B PlexTitration

Volume (mL)

I

0.8II

0.7III

0.6Average

0.6M equivalent MnO4-= M equivalent Fe2+

N.V MnO4- = N .V Fe2+0.102 x 0.7 = N x 25.00N Fe 2+= 2.448 x 10-3 NDasabion

Titration

Volume (mL)

I

15.8II

15.8III

15.9Average

15.9M equivalent MnO4-= M equivalent Fe2+

N.V MnO4- = N .V Fe2+0.102 x 15.9 = N x 25.00N Fe 2+= 0.064872 N

13The concentration of Fe2+ was determined.

Livron B PlexN = M x n N = 1

2.856 x 10-3 N = 1

Mass Fe 2+= 0.00799 gram = 7.99 mgramDasabionN = M x n

N = 1

0.064872 N = 1

Mass Fe 2+= 0.363 gram = 363 mgram

DiscussionMaking standard solution of KMnO4

In this experiment will be the determination of Fe2+ ion in solution was done by titration permanganometric. In this titration the titrant is acting as KMnO4 solution while the salt solution Fe2 + as its titrate. Standard solution of KMnO4created by 0790 grams of KMnO4 was dissolved in 250 mL aquades. From this process will form a purple solution. And then was boiled for 10 minutes. This warming aims to prevent the formation of the intermediate results in the form MnO2 thats have brown color. After the solution is boiled and then is filtered. The filtrate obtained from this screening are colored purple and there is little precipitate attached to the filter paper. As a secondary standard solution, before being used to standardize a reductant will be standardized KMnO4 solution prior to the primary standard. Primary standard solution is a reducing agent, in this experiment the primary standard solution used is sodium oxalate (Na2C2O4).Preparation of Primary standard solutions of Na2C2O4 0.1 NTo making a primary standard solution Na2C2O4 done by weighing as much as 1.675 grams of sodium oxalate and subsequent drying of the sodium oxalate is aiming to make the mass of sodium oxalate into constant given the nature of the sodium oxalate is hygroscopic. Once that phase is completed, the sodium oxalate is inserted into the 250 mL measuring flask previously filled with 50 mL of water and whipped until it dissolves. The continually added by aquades to limit the measuring flask.Standardization of KMnO4 solution by the primary standard solution Na2C2O4 0.1 NStandardization is a way to determine the appropriate concentration of standard solution. One way that can be used to standardize is by titration. Terms of use titration for standardization is to have available a solution whose concentration is known precisely. Solution in question is the primary standard solution. This solution was made from the primary standard substance, that is a substance concentration of the solution can be directly determined from weigh a certain amount of these substances and dissolving it in a certain volume.KMnO4 solution can be standardized with a solution Na2C2O4, where KMnO4 solution as titrant and solution of Na2C2O4 as its titrate. 25.0 ml of Na2C2O4 0.1 N entered into the erlenmeyer and added by 3 mL of concentrated H2SO4. The addition of concentrated H2SO4 was aimed to create an atmosphere of acid. Then the solution is heated to a temperature of about 70oC. The purpose of this warming is to prevent the formation of the intermediate results in the form of a brown MnO2. Titration was also carried out in hot conditions. In this acid solution of permanganate ion is reduced by the 5 electrons, when the oxidation state of Mn changes from +7 to +2. The reaction was as follows:MnO4- + H+ + 5 e- Mn2+ + 2 H2O

Titration was stopped until the solution color changed to pink titrates. In the process of standardization titration is done 3 times, where the number average volume of titrant (KMnO4) is 23. 97 mL. The reactions that occur in the standardization process are as follows:2 MnO4-(aq) + 16H+ + 5C2O42- (aq) 2 Mn2+(aq) + 8H2O(l) + 10CO2(g)Titration of Morh Salt SolutionN Fe2+= 0.1 N , V Fe2+= 100 mL= 0.1 L

N Fe2+= M.n

0.1 = 1 (( gr/Mr)/0.1 L)

Gram Fe 2+= (0.1 x 0.1 x 448.156) = 4.5 gramMohr salt solution prepared by dissolving 4.5 grams of Mohr salt in 100 mL aquades. A mixture of Morh salt with H2SO4 is then heated until the temperature 70o C. And then, titrated with standard KMnO4 solution that has been standardized. The average volume of KMnO4 that used is 22.81 mL. Titration was stopped when the color changed from light yellow of titrat into weak purple. Titration performed 3 times.

The reactions occurring in this titration is as follows: MnO4-(aq) + 8H+(aq) + 5Fe2+(aq) Mn2+(aq) + 5Fe3+(aq) + 4H2O(l)

Then obtained concentration of Fe2 + in the solution of salts based on the calculation result is observation 0.095 N and the percentage of Fe 2+ solution of salts is 13.40%V. Conclusion From the experimental results above it can be concluded that the concentration of Fe2 + in salts solution is 0095 N. VI. Answer of questions1. Na2C2O4 solution is good primary standard solution for permanganate in very acidic condition. In this experiment, addition of concentrated sulphuric acid into oxalate have purpose to make acidic solution. Other strong acid cannot be used, for example used HCl, Cl- will oxidized by KMnO4 to form Cl2 so the amount of KMnO4 that used is much, it caused the concentration of KMnO4 bigger than concentration that have to oxidized oxalate. It also occurs when the strong acid that use is HNO3.2. Reaction between oxalate and permanganate occur slowly in room temperature. It is caused the solution have to heat until the temperature is 70oC. The temperature also cannot more than 700C because if the temperature more than ith, reaction will occur slowly too. But, the speed of reaction increase when manganese (II) ion already formed. Manganese (II) ion has a function as catalyst, the reaction called by autokatalitik because it catalyst is produce in that reaction. This ion also give an effect by react quickly with permanganate to form manganese in midlle oxidation (+3 or +4), whereas it will quickly oxidized oxalate back to divalent condition.3. Beside ferro ion standardisation, permanganometric titration also can be used to standardized tin (II) ion. It is caused by tin (II) ion will oxidized to tin (IV) by KmnO4References

Selamat, I Nyoman dan I Gusti Lanang Wiratma.2004. Penuntun Praktikum Kimia Analitik. Singaraja: IKIP Negeri Singaraja.

Underwood, A.L dan RA day.2003.Analisis Kimia Kuantitatif .Jakarta: Erlangga

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