# Essay redox titration

942 Words Oct 24th, 2013 4 Pages
Determination of Vitamin C by Redox Titration with Iodine
Vitamin C (ascorbic acid) is an antioxidant that is essential for human nutrition. Vitamin C deficiency can lead to a disease called scurvy, which is characterized by abnormalities in the bones and teeth. Many fruits and vegetables contain vitamin C, but cooking destroys the vitamin, so raw citrus fruits and their juices are the main source of ascorbic acid for most people.
One way to determine the amount of vitamin C in food is to use a redox titration. The redox reaction is better than an acid-base titration since there are additional acids in a juice, but few of them interfere with the oxidation of ascorbic acid by iodine.
Iodine is relatively insoluble, but this can be
Repeat the titration until you have at least three measurement that agree to within 0.1 ml.
Titrating Real Lemon
Real Lemon is nice to use because the maker lists vitamin C, so you can compare your value with the packaged value.
1. Add 10.00 ml of Real Lemon into a 125 ml Erlenmeyer flask.
2. Titrate until you have at least three measurements that agree within 0.1 ml of iodine solution.
Other Samples
• Vitamin C Tablet - Dissolve the tablet in ~100 ml distilled water. Add distilled water to make 200 ml of solution in a volumetric flask.
• Fresh Fruit Juice - Strain the juice through a coffee filter or cheese cloth to remove pulp and seeds, since they could get stuck in the glassware.
• Packaged Fruit Juice - This also may require straining.
• Fruits & Vegetables - Blend a 100 g sample with ~50 ml of distilled water. Strain the mixture. Wash the filter with a few milliliters of distilled water. Add distilled water to make a final solution of 100 ml in a volumetric flask.
Titrate these samples in the same way as the juice sample described above.
Titration Calculations
1. Calculate the ml of titrant used for each flask. Take the measurements you obtained and average them. average volume = total volume / number of trials
2. Determine how much titrant was required for your standard.
If you needed an average of 10.00 ml of iodine solution to react 0.250 grams of vitamin C, then you can determine how much vitamin C was in a

## Related Documents

• ###### Essay Titration : The Concentration Of An Unknown Solution

Titration is used to determine the equivalence point of a reaction, or the point when the moles of acid are equal to the moles of base in a mixture. Titration is used to determine the concentration of an unknown solution by using an already known solution. This process is important because it is commonly in the medical field. For example, pharmacists use titration in the creation of drugs. In addition, doctors also titration when determining the concentration necessary to give their patients of different…

Words: 2054 - Pages: 9
• ###### Essay Titration : A Lab Experiment

where acetic acid and sulfuric acid solutions are neutralized using NaOH as a strong base, this process is known as titrating to find the endpoint. Titration is a technique designed to discover the molarity of an acid solution using a solution with a known molarity, in this experiment, NaOH was used. Titration required a color indicator to make the titration visible. In this lab, phenolphthalein was added to the solution so that the solution would turn light pink when the NaOH reached its endpoint. To…

Words: 790 - Pages: 4
• ###### Determination of Iron by Reaction with Permanganate-A Redox Titration

Determination of Iron by Reaction with Permanganate-A Redox Titration Purpose: The purpose of this experiment was to find the percentage of iron in an unknown iron oxide sample which could be determined through titration with a standard solution of potassium permanganate. Success in this analysis requires careful preparation and attention to detail. Performing this experiment also provides practice at titrations. The overall reaction is: 8H+(aq) + MnO4-(aq) + 5e-  Mn2+(aq) + 4H2O Theory:…

Words: 786 - Pages: 3
• ###### Virus Titration Essay

of cell culture: primary, this is cultivating the cells away from the parental tissue, secondary, which is when a primary culture is sub-cultured and cell lines, which can be continuous or finite depending on the life span of the culture. Virus titrations are used to estimate the virus concentration; it is a viral quantification technique. When detecting the virus, the cytopathic effect is looked at, whether there is lysis of the cells, vacuolation, formation of syncytia and the presence of inclusion…

Words: 971 - Pages: 4
• ###### The Acid Base Titrations And Indicator Titrations Introduction-

Title- Experiment #9- Acid Base Titrations II: Potentiometric and Indicator Titrations Introduction- In this experiment, the reactions of three different acids with a strong base are studied by observing how the pH of the solution changes as the titrant is added. A plot of pH versus amount of titrant added will be constructed. Such a curve is called a pH titration curve. The equivalence point of the reaction will be determined from an analysis of the pH titration curve, and by the use of acid-base…

Words: 1003 - Pages:
• ###### Essay Reaction Of Acid Base Titrations

Introduction Acid-base titrations are used to calculate properties of an acid or a base by titrating them with a strong Acid or base. In a titration, certain amount of volume of one substance usually a strong acid or base, a titrant, is added to another substance, an acid or base of some kind, until a change in properties are observed. Strong acids and bases are used because they allow the neutralization reaction between the acid and base into salt to go to completion. By titrating an unknown concentration…

Words: 738 - Pages: 3
• ###### Essay The Reactions Of The Redox Reaction Of Redox Reactions

CV of the redox reaction of the hydrolysate was measured at various concentrations. In the 80 °C bath, the initial hydrolysate concentration was 2% and was further diluted to 1% and 0.5%. Fig. 2(A) shows the CV curves, indicating the tendency and relation of current with varying potential (volt). As the hydrolysate dilution was increased, the maximum current density decreased. CV is widely used to obtain the voltammetry data. The cyclic voltamograms provides the information of the redox reaction…

Words: 1213 - Pages:
• ###### Experiment 5 Redox Titratio Essay

EXPERIMENT 5 REDOX TITRATION: TITRATION USING SODIUM THIOSULPHATE Objectives 1. 2. To prepare a standard solution of potassium iodate for use to determine the concentration of sodium thiosulphate solution accurately. To acquire the proper techniques of carrying out a titration. Introduction Redox titrations using sodium thiosulphate as a reducing agent is known as iodometric titration since it is used specifically to titrate iodine. The reaction involved is: I2 + 2Na2S2O3 I2 + 2S2O322NaI + Na2S4O6…

Words: 1140 - Pages: 5
• ###### Essay Titration : An Unknown Solution

Purpose Titration is a technique where an unknown solution’s concentration is determined with a solution of a known concentration. In this case, the known solution, NaOH, is dripped into the unknown, unknown #2, with a burette. The NaOH is dripped until the reaction is complete, while measuring the pH per amount of base added. Using the data collected, the equivalence point can be found and the concentration can be calculated. Then the KA can be found at specific points (20%, 40%, etc). After finding…

Words: 1192 - Pages:
• ###### Essay Water Hardness Titration

Title: Determination of Water Hardness Using a Titrator Purpose: To become familiar with the concept of water hardness, practice a titration technique using a titrator, and determine the hardness of the local water supply. Procedure: 1. Gather the test tube holder, small stopcock, 10-mL syringe (titrator), and 2 thick textbooks and the LabPaq box or 5-6 thick textbooks. 2. Remove the plunger from the titrator and place it back in your LabPaq box. 3. Attach the stopcock to the tip of…

Words: 1052 - Pages: 5