Acidimetry AND ALKALIMETRI
ABSTRACT
Acidimetry is titrimetric analysis using a strong acid as the analyte is titrannya and as a base or an alkaline compound. While in principle alkalimetri is titrimetric analysis using a strong base as titrannya and analyte is an acid or an acidic compound. This experiment aims to create a standard solution of 0.1 N HCl and the concentration of the solution set by means of standardization with a solution of borax and sodium carbonate anhydrous, create a primary standard solution of oxalic acid and acetic acid to determine the levels of trade.
In this experiment a solution prepared by dilution titration was then performed with standard solutions of certain so we get the price of diluting the concentration of the solution. Also in this experiment used titrimetric method to analyze the content of a sample of the process and alkalimetri acidimetry.
Experimental results obtained from the standardized solution of HCl is 0.0662 N and 0.867 N NaOH solution and the results are standardized 0.0113 N, while acetate levels studied were 0.24%, and NH3 levels contained in 0.2 grams of NH4Cl amounted to 10.75%.
Keywords: acidimetry, alkalimetri, the standard solution.
EXPERIMENT 1
Acidimetry AND ALKALIMETRI
1.1 Introduction
1.1.1 Objectives Experiment
The purpose of this experiment are:
A. Creating a standard solution of HCl 0.1 N and to determine the concentration of standard solution of HCl with a standardized way with a solution of borax (Na2B4O7.10H2O) and anhydrous Na2CO3.
2. Creating a standard solution of NaOH and standardized with oxalic acid.
3. Determine the levels of acid in vinegar traded and determine the levels of NH3 in the ammonium salt (NH4Cl).
1.1.2 Background
In principle acidimetry is titrimetric analysis using a strong acid as the analyte is titrannya and as a base or an alkaline compound, or measuring the acid (which measured the number of bases or salts). While in principle is alkalimetri titimetri analysis using a strong base as titrannya and the analyte is an acid or an acidic compound.
Solution commonly used as a titrant in alkalimetri is NaOH, KOH, and Ba (OH) 2 which is a standard solution of the secondary standard. Solution commonly used in this analysis because it is relatively inexpensive NaOH.
Indicators are often used in the experiment alkalimetri acidimetry and is an indicator of methyl red and methyl orange for acidimetry because the pH scale ranges on both indicators are in the acidic solution and an indicator for alkalimetri PP because PP indicator scale ranges of pH on the alkaline solution.
1.2 BASIC THEORY
In the analysis of acid and alkaline solution, the titration will involve a careful measurement of the volume-volume of an acid and an appropriate base menetra1kan each other. Neutralization reaction or acidimetry and alkalimetri is one of the four main groups in the classification of reactions in titrimetric analysis. Asidi alkalimetri involves titration of the free base or base formed by hydrolysis of salts derived from weak acids, with a standard (acidimetry) and titrate the free acid formed by hydrolysis of salts derived from weak bases, with a standard base (alkali metri). These reactions involve compounds of hydrogen ions and hydroxide ions to form water (Bassett, 1994).
Volumetric analysis is also known as titrimetry, in which substances are allowed to react with other substances known concentration and flow of the burette in solution form. Solution of unknown concentration (analyte) is then calculated. The condition is that the reaction must take place quickly, the reaction is quantitative and no side reactions (Khopkar, 1990).
In a reaction test to determine whether the reaction can be used for a titration, making the titration curve will help the understanding of acid-base titration to a titration curve consists of a groove or pOH pH versus mL of titrant. Such a curve is helpful in considering the feasibility of a titration and in selecting appropriate indicators (Underwood, 1999).
Inorganic substances can be classified into three important groups: acids, bases and salts. Acid is defined as a substance that when dissolved in water, dissociating with the formation of hydrogen ions as the only positive ions. Strong acids dissociate almost perfectly with the dilution medium, because he is a strong electrolyte. Weak acids dissociate only slightly in the concentration was even at low concentrations (Svehla, 1990).
Relatively strong acids and bases in solution depends on their affinity for different protons. The stronger the acid, the weaker its conjugate base. From the collection of chemical reactions known relatively little that can be used as the basis for the titration, a reaction to meet the following requirements prior to use.
A. The reaction must be run in accordance with a particular equation. There should be no side reactions.
2. The reaction had to walk up to virtually complete at the equivalence point. In other words, the reaction equilibrium constants must be very large.
3. Some method should be available to determine when the equivalence point is reached. A inidikator or some method must be available in the instrument can be used to inform the analysis is stopped when the addition of titrant.
4. The reaction runs quickly (in minutes)
(Day and Underwood, 1999).
For the acid-base indicators are usually made in the form of an aqueous acid-base indicators are substances that change color or form a fluorescent or turbidity in a range (route) a certain pH. Acid-base indicator is located at the equivalence point and the size of the pH. These substances may be an indicator of acid or base, soluble and stable and will show a strong color change, usually an organic substance (Khopkar, 1990).
Pure water has no taste, odor, and color. When it contains certain substances, water may tersa sour, bitter, salty, and so forth. Water that contains other substances can also be color. Sour liquid that is called an acid solution, which was called salty saline solution, whereas that feels slippery and bitter called the base solution (Shukri, 1999).
Inorganic substances can be classified into three important groups: acids, bases, and salts. Acid is most simply defined as a substance, which when dissolved in water, dissociating with the formation of hydrogen ions as the only positive ions. Basa, in the simplest can be defined as a substance, which when dissolved in IAR, dissociating with the formation of hydroxyl ions as the only negative ion (Svehla, 1979).
Ion in water containing very small amounts. This was caused by the occurrence of acid-base reaction among the molecules of water (autoionisasi) and establish the equilibrium:
H2O + H2O H3O + + OH-
In other words, water is a weak electrolyte and simplified into a H3O + when H +, the equilibrium is written as:
H2O H + + OH-
If the solution is acidic, then add the number of H +, and will shift the equilibrium to the left until a new equilibrium is reached. In the new equilibrium, the concentration of H + is greater than the OH-, but still perkaliannya 10-14. The same thing will happen when the water plus the bass so that the new equilibrium is achieved with a value of [OH-]> [H +] and remained perkaliannya 10-14.
Based on the ion concentration, the solution was divided into three, namely:
Acid solution: [H +]> [OH-]
Neutral solution [H +] = [OH-] = 10-7
Base solution: [H +] <[OH-]
(Shukri, 1999).
Titrimetric analysis is one of the major divisions in analytical chemistry. Calculations contained herein is based on the relationship stokiometrik of simple chemical reactions.
Titrimetric method of analysis based on chemical reactions such as:
aA + tT product
In which a molecule of the analyte, A, reacts with the reagent molecules t, T. Reagent T, called the titrant, is added continuously, usually from a burette, in the form of a solution of known concentration. This solution is called the standard solution, and its concentration determined by a process called standardization. The addition of titrant is still being done until the number of T is chemically the same as that has been added to A. then be said to be the equivalence point of titration was achieved. In order to know when to stop adding titrant, it can use chemicals, the indicators, which reacts to the presence of excess titrant with a color change. This discoloration may occur exactly at the equivalence point, but could not. Point in the titration where the indicator changes color is called the end point (Day and Underwood).
The indicator is a soluble dye which changes color as is evident in a narrow pH range. Typical types of indicators are weak organic acids that have a different color from its conjugate base. A good indicator has a color intensity such that only a few drops of dilute indicator solution should be added to the solution being tested. Concentration of molecules at a very low indicator is almost no effect on the pH of the solution. The color change indicator reflects the influence of other acids and bases contained in the solution (Oxtoby, 2001).
Chemical reactions may be treated as the basis of titrimetric determination has been grouped into four types:
a. Acid-Base. There are a large number of acids and bases which can be determined by titrimetry. If HA represents the acid to be determined, and B represents the base, are as follows rekasinya
HA + OH-A-+ H2O
and
BH + B + H3O + + H2O
b. Oxidation-reduction (redox). Chemical reaction involving oxidation-redoksi widely used in titrimetric analytical. For example, iron in the +2 oxidation rate can be titrated with a standard solution of cerium (IV) sulfate:
Fe2 + + Ce 4 + Fe3 + + Ce3 +
c. Deposition. Deposition of silver cations by halogen anions are widely used in the procedure titremetrik. His reaction is as follows
Ag + + X-AgX (s)
d. Complex formation. Examples of reactions in which a complex formed between silver and cyanide ion:
Ag + + 2 CN-Ag (CN) -2
(Oxtoby, 2001).
So far, relative few chemical reactions that could be used as a basis for the titration. A reaction must satisfy several conditions before the reaction can be used:
a. The reaction should be processed according to the equation given kimiwai. There should be no side effect.
b. The reaction should be processed until it is completely finished at the point of equivalence.
c. Should be available several methods to determine when the equivalence point is reached.
d. Reaction is expected to run faster, so that the titration can be completed within a few minutes (Day and Underwood, 1999).
1.3 METHODOLOGY EXPERIMENT
1.3.1 Tool
The tools used in this experiment is Bekker glass, Erlenmeyer, a graduated cylinder, volumetric flask, pipette drops, funnels, burette, watch glass, stir bar, and propipet volume pipette, spatula, analytical balance, heating.
Tools series:
Description:
1.buret
2. stative and klef
3. erlenmeyer
Figure 1.1 Tool titration
1.3.2 Material
The materials used in these experiments were concentrated HCl, distilled water, borax, Na2CO3, oxalic acid (H2C2O4.2H2O), ammonium chloride (NH4Cl), vinegar, PP indicator, methyl red indicator, the indicator orange metal, NaOH crystals
1.3.3 Experimental Procedure
1.3.3.1 Standardization of the Borax
A. Appropriately weigh 0.2 grams of borax, put into the Erlenmeyer and dissolve as much as 25 mL with distilled water and whisk until dissolved.
2. Add indicators as much as 3 drops of methyl red. Titrate with the HCl solution from the previous experiments so that the color change from yellow to pink. Titrannya volume recorded.
3. Conduct experiments on a total of two times.
1.3.3.2 Standardisation with anhydrous Na2CO3
A. Weighing 0.2 grams of Na2CO3. Dissolving in distilled water in a total of 60 mL erlenmeyer and shake well.
2. Add indicators as much as 3 drops orange metal. Titrate with the HCl solution until the color changed from orange to pink warma. Titrannya volume recorded.
3. Conduct experiments on a total of two times.
1.3.3.2 Standardization of NaOH with Oxalic Acid
A. Weighing 0.63 grams of oxalic acid with a watch glass. Entering into a 250 mL erlenmeyer. dissolve in water to a volume of 100 mL.
2. Take as many as 10 mL and add as many as 3 drops of indicator PP.
3. Titrate with NaOH until the solution becomes pink color and notes titrannya volume.
4. Conduct the experiment twice.
1.3.3.3 Determining the levels of NH3 in Ammonium Chloride
A. Weighing 0.2 grams NH4Cl and incorporate it into 250-ml erlenmeyer. Add 75 mL of NaOH solution that has been standardized.
2. Whisk well and heat until steam came out did not change the color of litmus paper that has been moistened with distilled water.
3. Add 3 drops of methyl red indicator and titrate with standard solution of HCl to the equivalence point.
4. Percoaan perform twice.
1.3.3.4 Determination of Levels of Amino Acids in Vinegar Traded
A. Weighed flask, then enter 5 mL vinegar, weighing more example, and then calculate the weight of cukanya acid.
2. Memipet 10 mL of vinegar into the erlenmeyer and add 3 drops of indicator PP.
3. Titrating with standard NaOH solution until the pink color. Titrannya volume recorded.
4. Conduct the experiment twice.
1.4 RESULTS AND DISCUSSION
1.4.1 Results
1.4.1.1 Acidimetry
1.4.1.1.1 Standardization of the Borax
Table 1.4.1 Standardization of the Borax
No. Step Experiment Observations
A. Weighing 0.2 grams Borax, dissolved in 25 ml distilled water as a homogeneous mixture is translucent colors
2. Add 3 drops of methyl red yellow color
3. Titrate with HCl V0 = 0 ml
V1 = 13.1 ml,
V = 13.1 ml
the color pink
1.4.1.1.2 Standardisation with anhydrous Na2CO3
Table 1.4.2 Standardisation with anhydrous Na2CO3
No. Step Experiment Observations
A. Weighing 0.2 grams Borax, dissolved in 25 ml distilled water as clear color
2. Add 3 drops of methyl orange yellow color
3. Titrate with HCl V0 = 0
V1 = 59.4 ml
V = 59.4 ml
1.4.1.2 Alkalimetri
1.4.1.2.1 Creating a standard solution of NaOH
Table 1.4.3 Creating Standard NaOH solution
No. Step Experiment Observations
A. Weighing 1 g NaOH, dissolve with V = 250 ml distilled water
1.4.1.2.2 Standardization of NaOH with Oxalic Acid
Table 1.4.4 Standardization of NaOH with Oxalic Acid
No. Step Experiment Observations
A. Weighing 0.6 grams of oxalic acid
2. Entering the erlenmeyer and add water V = 100 ml
3. Take as many as 10 ml solution of oxalic translucent colors
4. Add 3 drops of clear color PP
5. Titrate with NaOH ml V1 = 0, V2 = 10 ml
V = 10 ml
the color pink
1.4.1.2.3 Determining the levels of NH3 in NH4Cl
Table 1.4.5 Determining the levels of NH3 in NH4Cl
No. Step Experiment Observations
A. Considering NH4Cl, enter into erlenmeyer, add a solution of NaOH in 75 ml of 0.2 g mass
2. Whisk and heat the transparent color
3. Add 3 drops of methyl red-yellow color
4. Titrate with HCl ml V1 = 0, V2 = 59.4 ml
V = 59.4 ml
pink
1.4.1.2.3 Determining the levels of acid in vinegar traded
Table 1.4.6 Determining the levels of acid in vinegar traded
No. Step Experiment Observations
A. Weighing 195.9 grams of empty bottles
2. Considering acetic acid + 5 ml bottle is empty
Weight of acetic acid =
200.4 to 195.9 = 4.5 grams
3. Incorporate vinegar into a 250 ml volumetric flask and add distilled water
to mark boundaries V = 250 ml
3. Memipet 10 ml of vinegar into the erlenmeyer and add 3 drops of indicator PP
clear color
4. Titrating with standard NaOH ml V1 = 0, V1 = 1.7 ml
V = 1.7 ml
1.4.2 Discussion
1.4.2.1 Acidimetry
1.4.2.1.1 Standardization of the Borax
The first is to make a solution of borax, borax mass to make a standard solution that is 0.2 grams. BM borax = 384.4 g / mol and the total dilution volume of 25ml. Of several variables on the reaction solvent borax can be seen as follows:
Na2B4O7 H2B4O7 2H2O + NaOH + 2
After that add the red metal indicator so that as many as 3 drops of the color changes to yellow in borax. This is because the indicator methyl red has a pH of 4.2 to 6.3 yellow route if the alkaline solution. Then the solution was titrated with 0.1 N HCl Titration was performed until the yellow color changed to pink. This discoloration is due to the H + ion from HCl and this change marked the end point of titration. HCl solution was standardized by titration Na2B4O7.10H2O intended to eliminate the CO2 gas that is formed so as to make the indicator change the color of the solution
The reaction is as follows:
Na2B4O7.10H2O + + 2HCl 4H3BO3 2NaCl + · 5H2O
or Na2B4O7.5H2O + + 2HCl 2NaCl 4H3BO4
From the data obtained can be calculated normality of a solution of HCl is 0.077 N.
1.4.2.1.2 Standardisation with anhydrous Na2CO3
Standardization of HCl solution made by dissolving 0.2 grams of Na2CO3 and make up to volume 60 ml dilution. Then added with 3 drops of methyl-orange indicator, and then titrated with a solution of HCl. Na2CO3 solution acts as a default solution because kepekatannya known in molarity.
The reaction between Na2CO3 and HCl that occur are:
2Na + +2 + CO3-H2CO3 HCl + Cl +2 NaCl
In a brief written:
Na2CO3 + H2O + CO2 2NaCl
Repetition of the experiment can be titrated volume of 59.4 ml and the concentration of Na2CO3 of 0.0628 N and 0.0594 for V titrant, V titrannya because pH at the titration end point is greater than the pH indicator methyl red route. PH at the first titration end point is 8.3 for NaHCO3 salts formed a slightly alkaline pH and route of methyl red indicator parlu HCl from 4.4 to 6.2 so many to reach the route PH
1.4.2.2 Alkalimetri
1.4.2.2 Preparation of standard solution of NaOH 1
In this experiment the standard NaOH solution obtained by dissolving 1 gram of NaOH to 250 ml with distilled water. NaOH solution in a previously heated to be crushed and dissolved solids with distilled water. Standard solution of NaOH used for further calculations, and to titrate.
NaOH dissolution reaction is as follows:
H2O + NaOH Na + + OH-+ H2O
Based on calculations derived NaOH concentration of 0.1 N.
1.4.2.2.2 Standardization of NaOH with oxalic acid
At the time of a solution of oxalic acid is titrated with standard NaOH solution previously generated a reaction occurs as follows:
C2H2O4. 2H2O + NaOH + CO2 + H2O NaCHO4
The titration was stopped after the solution is initially translucent color turns pink. The color change occurs indicates that the equivalence point has been reached, after titration with NaOH normality obtained was 0.1332 N oxalic acid and 0.1 N NaOH for V titrannya because oxalic acid requires OH-ion is much more to reach the equivalence point so that the volume of titrant dipergunakanpun more.
1.4.2.2.3 Determination of levels of NH3 in Ammonium Chloride
To find out how much the content of NH3 in NH4Cl, first weighing is done as much as 0.2 grams of NH4Cl included in the erlenmeyer and then added 75 ml of NaOH solution has been made then shaken and heated. Drops of methyl red after new heated titrated with HCl
At the time of addition of NaOH to a solution of NH4Cl, the reaction occurs as follows:
NH4Cl + NaOH NaCl + H2O + NH3
Titration the following reaction:
HCl + NaOH NaCl + H2O
From the calculation results obtained in NH4Cl NH3 levels at 50.45%, V same as above titration of PH at the end point. Fewer base titration, as there is a weak base ammonia, and pH indicator methyl red trajectory of 4.4 to 6.2, so it needs more HCl.
1.4.2.2.4 Determination of acidity in the vinegar-traded
In this experiment, praktikan use vinegar as a sample brick cap. Initially taken a lot of vinegar 5 ml, then determined the weight and diluted. After that PP added indicator to indicate the end point when the vinegar was titrated with NaOH standard solution.
Reactions that occur during the titration as follows:
CH3COOH + NaOH + H2O CH3COONa
Acetic acid (CH3COOH) is one example protolit weak, the molecule or ion that can be gained with the balance of acidic protons is determined by the constant protolisisnya basanya. Vinegar or acetic acid are known to frequently used should be diluted with water first because if it is not harmful to the wearer.
Calculation of vinegar acid levels was performed to compare levels of acid contained in the label with the experiments performed. In 5 ml vinegar sample contained 0.0816 grams of CH3COOH to levels around 1.8133%.
1.5 CONCLUSION
1.5.1 Conclusion
A. To standardize a solution of 0.0418 N BORAX required by 25 ml 0.0134 ml or 13.4 ml of HCl solution with a concentration of normality of 0.0779 N
2. Standard solution of HCl 0.1 N as much as 59.4 ml is used to standardize the Na2CO3 solution with a concentration of 0.0634 N normality
3. To make 1 gram of NaOH with a concentration of normality of 0.1 N
4. In the standardized solution of 0.1332 N oxalic needed as much as 100 ml 1 N NaOH standard solution of 10 ml
5. NH3 levels are contained in 0.2 grams of NH4Cl is 50.45%
6. Acid levels contained in 5 ml vinegar bottle cap is equal to 1.8133%.
1.5.2 Suggestions
A. Tools should be used at trial insufficient and in accordance with the experiments, so praktikan not get into trouble because of lack of equipment.
2. Laboratory assistant jobs should pay more attention to avoid mistakes praktikan procedure.
ABSTRACT
Acidimetry is titrimetric analysis using a strong acid as the analyte is titrannya and as a base or an alkaline compound. While in principle alkalimetri is titrimetric analysis using a strong base as titrannya and analyte is an acid or an acidic compound. This experiment aims to create a standard solution of 0.1 N HCl and the concentration of the solution set by means of standardization with a solution of borax and sodium carbonate anhydrous, create a primary standard solution of oxalic acid and acetic acid to determine the levels of trade.
In this experiment a solution prepared by dilution titration was then performed with standard solutions of certain so we get the price of diluting the concentration of the solution. Also in this experiment used titrimetric method to analyze the content of a sample of the process and alkalimetri acidimetry.
Experimental results obtained from the standardized solution of HCl is 0.0662 N and 0.867 N NaOH solution and the results are standardized 0.0113 N, while acetate levels studied were 0.24%, and NH3 levels contained in 0.2 grams of NH4Cl amounted to 10.75%.
Keywords: acidimetry, alkalimetri, the standard solution.
EXPERIMENT 1
Acidimetry AND ALKALIMETRI
1.1 Introduction
1.1.1 Objectives Experiment
The purpose of this experiment are:
A. Creating a standard solution of HCl 0.1 N and to determine the concentration of standard solution of HCl with a standardized way with a solution of borax (Na2B4O7.10H2O) and anhydrous Na2CO3.
2. Creating a standard solution of NaOH and standardized with oxalic acid.
3. Determine the levels of acid in vinegar traded and determine the levels of NH3 in the ammonium salt (NH4Cl).
1.1.2 Background
In principle acidimetry is titrimetric analysis using a strong acid as the analyte is titrannya and as a base or an alkaline compound, or measuring the acid (which measured the number of bases or salts). While in principle is alkalimetri titimetri analysis using a strong base as titrannya and the analyte is an acid or an acidic compound.
Solution commonly used as a titrant in alkalimetri is NaOH, KOH, and Ba (OH) 2 which is a standard solution of the secondary standard. Solution commonly used in this analysis because it is relatively inexpensive NaOH.
Indicators are often used in the experiment alkalimetri acidimetry and is an indicator of methyl red and methyl orange for acidimetry because the pH scale ranges on both indicators are in the acidic solution and an indicator for alkalimetri PP because PP indicator scale ranges of pH on the alkaline solution.
1.2 BASIC THEORY
In the analysis of acid and alkaline solution, the titration will involve a careful measurement of the volume-volume of an acid and an appropriate base menetra1kan each other. Neutralization reaction or acidimetry and alkalimetri is one of the four main groups in the classification of reactions in titrimetric analysis. Asidi alkalimetri involves titration of the free base or base formed by hydrolysis of salts derived from weak acids, with a standard (acidimetry) and titrate the free acid formed by hydrolysis of salts derived from weak bases, with a standard base (alkali metri). These reactions involve compounds of hydrogen ions and hydroxide ions to form water (Bassett, 1994).
Volumetric analysis is also known as titrimetry, in which substances are allowed to react with other substances known concentration and flow of the burette in solution form. Solution of unknown concentration (analyte) is then calculated. The condition is that the reaction must take place quickly, the reaction is quantitative and no side reactions (Khopkar, 1990).
In a reaction test to determine whether the reaction can be used for a titration, making the titration curve will help the understanding of acid-base titration to a titration curve consists of a groove or pOH pH versus mL of titrant. Such a curve is helpful in considering the feasibility of a titration and in selecting appropriate indicators (Underwood, 1999).
Inorganic substances can be classified into three important groups: acids, bases and salts. Acid is defined as a substance that when dissolved in water, dissociating with the formation of hydrogen ions as the only positive ions. Strong acids dissociate almost perfectly with the dilution medium, because he is a strong electrolyte. Weak acids dissociate only slightly in the concentration was even at low concentrations (Svehla, 1990).
Relatively strong acids and bases in solution depends on their affinity for different protons. The stronger the acid, the weaker its conjugate base. From the collection of chemical reactions known relatively little that can be used as the basis for the titration, a reaction to meet the following requirements prior to use.
A. The reaction must be run in accordance with a particular equation. There should be no side reactions.
2. The reaction had to walk up to virtually complete at the equivalence point. In other words, the reaction equilibrium constants must be very large.
3. Some method should be available to determine when the equivalence point is reached. A inidikator or some method must be available in the instrument can be used to inform the analysis is stopped when the addition of titrant.
4. The reaction runs quickly (in minutes)
(Day and Underwood, 1999).
For the acid-base indicators are usually made in the form of an aqueous acid-base indicators are substances that change color or form a fluorescent or turbidity in a range (route) a certain pH. Acid-base indicator is located at the equivalence point and the size of the pH. These substances may be an indicator of acid or base, soluble and stable and will show a strong color change, usually an organic substance (Khopkar, 1990).
Pure water has no taste, odor, and color. When it contains certain substances, water may tersa sour, bitter, salty, and so forth. Water that contains other substances can also be color. Sour liquid that is called an acid solution, which was called salty saline solution, whereas that feels slippery and bitter called the base solution (Shukri, 1999).
Inorganic substances can be classified into three important groups: acids, bases, and salts. Acid is most simply defined as a substance, which when dissolved in water, dissociating with the formation of hydrogen ions as the only positive ions. Basa, in the simplest can be defined as a substance, which when dissolved in IAR, dissociating with the formation of hydroxyl ions as the only negative ion (Svehla, 1979).
Ion in water containing very small amounts. This was caused by the occurrence of acid-base reaction among the molecules of water (autoionisasi) and establish the equilibrium:
H2O + H2O H3O + + OH-
In other words, water is a weak electrolyte and simplified into a H3O + when H +, the equilibrium is written as:
H2O H + + OH-
If the solution is acidic, then add the number of H +, and will shift the equilibrium to the left until a new equilibrium is reached. In the new equilibrium, the concentration of H + is greater than the OH-, but still perkaliannya 10-14. The same thing will happen when the water plus the bass so that the new equilibrium is achieved with a value of [OH-]> [H +] and remained perkaliannya 10-14.
Based on the ion concentration, the solution was divided into three, namely:
Acid solution: [H +]> [OH-]
Neutral solution [H +] = [OH-] = 10-7
Base solution: [H +] <[OH-]
(Shukri, 1999).
Titrimetric analysis is one of the major divisions in analytical chemistry. Calculations contained herein is based on the relationship stokiometrik of simple chemical reactions.
Titrimetric method of analysis based on chemical reactions such as:
aA + tT product
In which a molecule of the analyte, A, reacts with the reagent molecules t, T. Reagent T, called the titrant, is added continuously, usually from a burette, in the form of a solution of known concentration. This solution is called the standard solution, and its concentration determined by a process called standardization. The addition of titrant is still being done until the number of T is chemically the same as that has been added to A. then be said to be the equivalence point of titration was achieved. In order to know when to stop adding titrant, it can use chemicals, the indicators, which reacts to the presence of excess titrant with a color change. This discoloration may occur exactly at the equivalence point, but could not. Point in the titration where the indicator changes color is called the end point (Day and Underwood).
The indicator is a soluble dye which changes color as is evident in a narrow pH range. Typical types of indicators are weak organic acids that have a different color from its conjugate base. A good indicator has a color intensity such that only a few drops of dilute indicator solution should be added to the solution being tested. Concentration of molecules at a very low indicator is almost no effect on the pH of the solution. The color change indicator reflects the influence of other acids and bases contained in the solution (Oxtoby, 2001).
Chemical reactions may be treated as the basis of titrimetric determination has been grouped into four types:
a. Acid-Base. There are a large number of acids and bases which can be determined by titrimetry. If HA represents the acid to be determined, and B represents the base, are as follows rekasinya
HA + OH-A-+ H2O
and
BH + B + H3O + + H2O
b. Oxidation-reduction (redox). Chemical reaction involving oxidation-redoksi widely used in titrimetric analytical. For example, iron in the +2 oxidation rate can be titrated with a standard solution of cerium (IV) sulfate:
Fe2 + + Ce 4 + Fe3 + + Ce3 +
c. Deposition. Deposition of silver cations by halogen anions are widely used in the procedure titremetrik. His reaction is as follows
Ag + + X-AgX (s)
d. Complex formation. Examples of reactions in which a complex formed between silver and cyanide ion:
Ag + + 2 CN-Ag (CN) -2
(Oxtoby, 2001).
So far, relative few chemical reactions that could be used as a basis for the titration. A reaction must satisfy several conditions before the reaction can be used:
a. The reaction should be processed according to the equation given kimiwai. There should be no side effect.
b. The reaction should be processed until it is completely finished at the point of equivalence.
c. Should be available several methods to determine when the equivalence point is reached.
d. Reaction is expected to run faster, so that the titration can be completed within a few minutes (Day and Underwood, 1999).
1.3 METHODOLOGY EXPERIMENT
1.3.1 Tool
The tools used in this experiment is Bekker glass, Erlenmeyer, a graduated cylinder, volumetric flask, pipette drops, funnels, burette, watch glass, stir bar, and propipet volume pipette, spatula, analytical balance, heating.
Tools series:
Description:
1.buret
2. stative and klef
3. erlenmeyer
Figure 1.1 Tool titration
1.3.2 Material
The materials used in these experiments were concentrated HCl, distilled water, borax, Na2CO3, oxalic acid (H2C2O4.2H2O), ammonium chloride (NH4Cl), vinegar, PP indicator, methyl red indicator, the indicator orange metal, NaOH crystals
1.3.3 Experimental Procedure
1.3.3.1 Standardization of the Borax
A. Appropriately weigh 0.2 grams of borax, put into the Erlenmeyer and dissolve as much as 25 mL with distilled water and whisk until dissolved.
2. Add indicators as much as 3 drops of methyl red. Titrate with the HCl solution from the previous experiments so that the color change from yellow to pink. Titrannya volume recorded.
3. Conduct experiments on a total of two times.
1.3.3.2 Standardisation with anhydrous Na2CO3
A. Weighing 0.2 grams of Na2CO3. Dissolving in distilled water in a total of 60 mL erlenmeyer and shake well.
2. Add indicators as much as 3 drops orange metal. Titrate with the HCl solution until the color changed from orange to pink warma. Titrannya volume recorded.
3. Conduct experiments on a total of two times.
1.3.3.2 Standardization of NaOH with Oxalic Acid
A. Weighing 0.63 grams of oxalic acid with a watch glass. Entering into a 250 mL erlenmeyer. dissolve in water to a volume of 100 mL.
2. Take as many as 10 mL and add as many as 3 drops of indicator PP.
3. Titrate with NaOH until the solution becomes pink color and notes titrannya volume.
4. Conduct the experiment twice.
1.3.3.3 Determining the levels of NH3 in Ammonium Chloride
A. Weighing 0.2 grams NH4Cl and incorporate it into 250-ml erlenmeyer. Add 75 mL of NaOH solution that has been standardized.
2. Whisk well and heat until steam came out did not change the color of litmus paper that has been moistened with distilled water.
3. Add 3 drops of methyl red indicator and titrate with standard solution of HCl to the equivalence point.
4. Percoaan perform twice.
1.3.3.4 Determination of Levels of Amino Acids in Vinegar Traded
A. Weighed flask, then enter 5 mL vinegar, weighing more example, and then calculate the weight of cukanya acid.
2. Memipet 10 mL of vinegar into the erlenmeyer and add 3 drops of indicator PP.
3. Titrating with standard NaOH solution until the pink color. Titrannya volume recorded.
4. Conduct the experiment twice.
1.4 RESULTS AND DISCUSSION
1.4.1 Results
1.4.1.1 Acidimetry
1.4.1.1.1 Standardization of the Borax
Table 1.4.1 Standardization of the Borax
No. Step Experiment Observations
A. Weighing 0.2 grams Borax, dissolved in 25 ml distilled water as a homogeneous mixture is translucent colors
2. Add 3 drops of methyl red yellow color
3. Titrate with HCl V0 = 0 ml
V1 = 13.1 ml,
V = 13.1 ml
the color pink
1.4.1.1.2 Standardisation with anhydrous Na2CO3
Table 1.4.2 Standardisation with anhydrous Na2CO3
No. Step Experiment Observations
A. Weighing 0.2 grams Borax, dissolved in 25 ml distilled water as clear color
2. Add 3 drops of methyl orange yellow color
3. Titrate with HCl V0 = 0
V1 = 59.4 ml
V = 59.4 ml
1.4.1.2 Alkalimetri
1.4.1.2.1 Creating a standard solution of NaOH
Table 1.4.3 Creating Standard NaOH solution
No. Step Experiment Observations
A. Weighing 1 g NaOH, dissolve with V = 250 ml distilled water
1.4.1.2.2 Standardization of NaOH with Oxalic Acid
Table 1.4.4 Standardization of NaOH with Oxalic Acid
No. Step Experiment Observations
A. Weighing 0.6 grams of oxalic acid
2. Entering the erlenmeyer and add water V = 100 ml
3. Take as many as 10 ml solution of oxalic translucent colors
4. Add 3 drops of clear color PP
5. Titrate with NaOH ml V1 = 0, V2 = 10 ml
V = 10 ml
the color pink
1.4.1.2.3 Determining the levels of NH3 in NH4Cl
Table 1.4.5 Determining the levels of NH3 in NH4Cl
No. Step Experiment Observations
A. Considering NH4Cl, enter into erlenmeyer, add a solution of NaOH in 75 ml of 0.2 g mass
2. Whisk and heat the transparent color
3. Add 3 drops of methyl red-yellow color
4. Titrate with HCl ml V1 = 0, V2 = 59.4 ml
V = 59.4 ml
pink
1.4.1.2.3 Determining the levels of acid in vinegar traded
Table 1.4.6 Determining the levels of acid in vinegar traded
No. Step Experiment Observations
A. Weighing 195.9 grams of empty bottles
2. Considering acetic acid + 5 ml bottle is empty
Weight of acetic acid =
200.4 to 195.9 = 4.5 grams
3. Incorporate vinegar into a 250 ml volumetric flask and add distilled water
to mark boundaries V = 250 ml
3. Memipet 10 ml of vinegar into the erlenmeyer and add 3 drops of indicator PP
clear color
4. Titrating with standard NaOH ml V1 = 0, V1 = 1.7 ml
V = 1.7 ml
1.4.2 Discussion
1.4.2.1 Acidimetry
1.4.2.1.1 Standardization of the Borax
The first is to make a solution of borax, borax mass to make a standard solution that is 0.2 grams. BM borax = 384.4 g / mol and the total dilution volume of 25ml. Of several variables on the reaction solvent borax can be seen as follows:
Na2B4O7 H2B4O7 2H2O + NaOH + 2
After that add the red metal indicator so that as many as 3 drops of the color changes to yellow in borax. This is because the indicator methyl red has a pH of 4.2 to 6.3 yellow route if the alkaline solution. Then the solution was titrated with 0.1 N HCl Titration was performed until the yellow color changed to pink. This discoloration is due to the H + ion from HCl and this change marked the end point of titration. HCl solution was standardized by titration Na2B4O7.10H2O intended to eliminate the CO2 gas that is formed so as to make the indicator change the color of the solution
The reaction is as follows:
Na2B4O7.10H2O + + 2HCl 4H3BO3 2NaCl + · 5H2O
or Na2B4O7.5H2O + + 2HCl 2NaCl 4H3BO4
From the data obtained can be calculated normality of a solution of HCl is 0.077 N.
1.4.2.1.2 Standardisation with anhydrous Na2CO3
Standardization of HCl solution made by dissolving 0.2 grams of Na2CO3 and make up to volume 60 ml dilution. Then added with 3 drops of methyl-orange indicator, and then titrated with a solution of HCl. Na2CO3 solution acts as a default solution because kepekatannya known in molarity.
The reaction between Na2CO3 and HCl that occur are:
2Na + +2 + CO3-H2CO3 HCl + Cl +2 NaCl
In a brief written:
Na2CO3 + H2O + CO2 2NaCl
Repetition of the experiment can be titrated volume of 59.4 ml and the concentration of Na2CO3 of 0.0628 N and 0.0594 for V titrant, V titrannya because pH at the titration end point is greater than the pH indicator methyl red route. PH at the first titration end point is 8.3 for NaHCO3 salts formed a slightly alkaline pH and route of methyl red indicator parlu HCl from 4.4 to 6.2 so many to reach the route PH
1.4.2.2 Alkalimetri
1.4.2.2 Preparation of standard solution of NaOH 1
In this experiment the standard NaOH solution obtained by dissolving 1 gram of NaOH to 250 ml with distilled water. NaOH solution in a previously heated to be crushed and dissolved solids with distilled water. Standard solution of NaOH used for further calculations, and to titrate.
NaOH dissolution reaction is as follows:
H2O + NaOH Na + + OH-+ H2O
Based on calculations derived NaOH concentration of 0.1 N.
1.4.2.2.2 Standardization of NaOH with oxalic acid
At the time of a solution of oxalic acid is titrated with standard NaOH solution previously generated a reaction occurs as follows:
C2H2O4. 2H2O + NaOH + CO2 + H2O NaCHO4
The titration was stopped after the solution is initially translucent color turns pink. The color change occurs indicates that the equivalence point has been reached, after titration with NaOH normality obtained was 0.1332 N oxalic acid and 0.1 N NaOH for V titrannya because oxalic acid requires OH-ion is much more to reach the equivalence point so that the volume of titrant dipergunakanpun more.
1.4.2.2.3 Determination of levels of NH3 in Ammonium Chloride
To find out how much the content of NH3 in NH4Cl, first weighing is done as much as 0.2 grams of NH4Cl included in the erlenmeyer and then added 75 ml of NaOH solution has been made then shaken and heated. Drops of methyl red after new heated titrated with HCl
At the time of addition of NaOH to a solution of NH4Cl, the reaction occurs as follows:
NH4Cl + NaOH NaCl + H2O + NH3
Titration the following reaction:
HCl + NaOH NaCl + H2O
From the calculation results obtained in NH4Cl NH3 levels at 50.45%, V same as above titration of PH at the end point. Fewer base titration, as there is a weak base ammonia, and pH indicator methyl red trajectory of 4.4 to 6.2, so it needs more HCl.
1.4.2.2.4 Determination of acidity in the vinegar-traded
In this experiment, praktikan use vinegar as a sample brick cap. Initially taken a lot of vinegar 5 ml, then determined the weight and diluted. After that PP added indicator to indicate the end point when the vinegar was titrated with NaOH standard solution.
Reactions that occur during the titration as follows:
CH3COOH + NaOH + H2O CH3COONa
Acetic acid (CH3COOH) is one example protolit weak, the molecule or ion that can be gained with the balance of acidic protons is determined by the constant protolisisnya basanya. Vinegar or acetic acid are known to frequently used should be diluted with water first because if it is not harmful to the wearer.
Calculation of vinegar acid levels was performed to compare levels of acid contained in the label with the experiments performed. In 5 ml vinegar sample contained 0.0816 grams of CH3COOH to levels around 1.8133%.
1.5 CONCLUSION
1.5.1 Conclusion
A. To standardize a solution of 0.0418 N BORAX required by 25 ml 0.0134 ml or 13.4 ml of HCl solution with a concentration of normality of 0.0779 N
2. Standard solution of HCl 0.1 N as much as 59.4 ml is used to standardize the Na2CO3 solution with a concentration of 0.0634 N normality
3. To make 1 gram of NaOH with a concentration of normality of 0.1 N
4. In the standardized solution of 0.1332 N oxalic needed as much as 100 ml 1 N NaOH standard solution of 10 ml
5. NH3 levels are contained in 0.2 grams of NH4Cl is 50.45%
6. Acid levels contained in 5 ml vinegar bottle cap is equal to 1.8133%.
1.5.2 Suggestions
A. Tools should be used at trial insufficient and in accordance with the experiments, so praktikan not get into trouble because of lack of equipment.
2. Laboratory assistant jobs should pay more attention to avoid mistakes praktikan procedure.
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