Article
Ascorbic Acid as a Standard for Iodometric Titrations. An Analytical Experiment for General Chemistry
Purchase the full-text
- PDF/HTML,
figures/images,
references and tables,
(where available)
Abstract
Ascorbic acid is suggested as the weighable compound for the standardization of iodine solutions in an analytical experiment in general chemistry. The experiment involves an iodometric titration in which iodine reacts with ascorbic acid, oxidizing it to dehydroascorbic acid. The redox titration endpoint is determined by the first iodine excess that is complexed with starch, giving a deep blue-violet color. The results of the titration of iodine solution using ascorbic acid as a calibration standard were compared with the results acquired by the classic method using a standardized solution of sodium thiosulfate. The standardization of the iodine solution using ascorbic acid was accurate and precise, with the advantages of saving time and avoiding mistakes due to solution preparation. The colorless ascorbic acid solution gives a very clear and sharp titration end point with starch. It was shown by thermogravimetric analysis that ascorbic acid can be dried at 393 K for 2 h without decomposition. This experiment allows general chemistry students to perform an iodometric titration during a single laboratory period, determining with precision the content of vitamin C in pharmaceutical formulations.
Keywords (Audience):
High School / Introductory ChemistryKeywords (Domain):
Laboratory InstructionKeywords (Pedagogy):
Hands-On Learning / ManipulativesKeywords (Subject):
Oxidation / ReductionCiting Articles
Citation data is made available by participants in CrossRef's Cited-by Linking service. For a more comprehensive list of citations to this article, users are encouraged to perform a search in SciFinder.
This article has been cited by 5 ACS Journal articles (5 most recent appear below).

Mechanistic Studies on the Oxidation of Ascorbic Acid and Hydroquinone by a {Mn4O6}4+ Core in Aqueous Media
Maharudra Chakraborty, N. Jiten Singh, Pulak Chandra Mandal, Suranjana Das, and Subrata MukhopadhyayThe Journal of Physical Chemistry A2011 Article ASAPMechanistic Studies on the Oxidation of Ascorbic Acid and Hydroquinone by a {Mn4O6}4+ Core in Aqueous Media
Maharudra Chakraborty, N. Jiten Singh, Pulak Chandra Mandal, Suranjana Das, and Subrata MukhopadhyayThe Journal of Physical Chemistry A2011 Article ASAPDescribed in this work is the kinetics of oxidation of ascorbic acid and hydroquinone by a tetranuclear Mn(IV) oxidant, [Mn4(μ-O)6(bipy)6]4+ (14+, bipy =2,2/-bipyridine), in aqueous solution over a wide pH range 1.5–6.0. In particular, below pH 3.0, ...

Measuring Vitamin C Content of Commercial Orange Juice Using a Pencil Lead Electrode
David King, Jeffrey Friend and James KariukiJournal of Chemical Education2010 87 (5), 507-509Measuring Vitamin C Content of Commercial Orange Juice Using a Pencil Lead Electrode
David King, Jeffrey Friend and James KariukiJournal of Chemical Education2010 87 (5), 507-509A pencil lead successfully served as an electrode for the determination of ascorbic acid in commercial orange juice. Cyclic voltammetry was used as an electrochemical probe to measure the current produced from the oxidation of ascorbic acid with a variety ...

Principles of Solution Thermodynamics: Demonstration of Nonideal Behavior of Henry's Law. An Undergraduate Laboratory Experiment
Luke Chandler Short and Thorsten BenterJournal of Chemical Education2006 83 (8), 1233Principles of Solution Thermodynamics: Demonstration of Nonideal Behavior of Henry's Law. An Undergraduate Laboratory Experiment
Luke Chandler Short and Thorsten BenterJournal of Chemical Education2006 83 (8), 1233Quantitative analysis of formaldehyde, HCHO, using the Nash reaction has seen a wide application in both the fields of environmental chemistry and medicine. Our group uses portable Nash systems both to monitor trace levels of HCHO (ppbV, 1/109) present in ...

Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes: A High School or General Chemistry Experiment
Samuella B. Sigmann and Dale E. WheelerJournal of Chemical Education2004 81 (10), 1479Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes: A High School or General Chemistry Experiment
Samuella B. Sigmann and Dale E. WheelerJournal of Chemical Education2004 81 (10), 1479This article provides a method to quantitatively determine the amount of both citric and ascorbic acid in a given sample of a powdered drink mix. The total moles of acid in the sample are determined by titration with sodium hydroxide. Moles of ascorbic ...

Standardizing Iodine (about J. Chem. Educ. 1999, 76, 1421-1422)
Stephen J. HawkesJournal of Chemical Education2000 77 (12), 1557Standardizing Iodine (about J. Chem. Educ. 1999, 76, 1421-1422)
Stephen J. HawkesJournal of Chemical Education2000 77 (12), 1557
Tools
-
Add to Favorites
-
Download Citation
-
Email a Colleague -
Permalink
Order Reprints
Rights & Permissions
Citation Alerts
History
- Received: August 03, 2009
Cart
ACS
Network






