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• Blue iodine. It may take the form of generalized argyria or local argyria. Dec 16, 2022 · The nature of the blue color in the iodine-starch reaction (or, in most cases, iodine-iodide-starch reaction, i. It may be used in first aid for minor cuts, burns, abrasions and blisters. The coloring can be differentiated outwardly with centralizations of iodine as low as 2×10-5 Apr 21, 2022 · The iodine test is a chemical reaction-based identification test for starch. The radiation in the iodine destroys thyroid tumor cells and effectively cures hyperthyroidism. Has shown its miraculous properties in the most difficult conditions of human survival. It helps to regulate the production of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). The reaction is due to the formation of polyiodide chains from the reaction of starch and iodine. 5. as I2 as well as I- are typically present) has for decades elicited debate. Iodine is an essential element for humans, who need a daily intake of about 0. The amount of thiosulfate ions added tells us how much iodine had been produced in the time taken for the reaction to turn blue. 66. The “clock reaction” is a reaction famous for its dramatic colorless-to-blue color change, and is often used. Iodine reacts with bases to make hypoiodite and iodide. Routine use of these tissue stains was found to be sensitive and specific. When you put iodine on the leaves, one of them will turn blue-black and the other will be a reddish-brown. Getting Iodine produces a charge-transfer complex with starch, producing an intense color. Toluidine blue stains esophageal malignancies and dysplasia, although Lugol's iodine solution has supplanted it to a great extent. The iodine test is used to differentiate polysaccharides from monosaccharides and disaccharides. AKA: Instant Coke, Instant Wine, 30-second Coke. The new spacings absorb visible light differently and create the deep blue color. reacts with starch to form a dark blue iodine/starch complex. Iodine is an essential element that is needed to produce thyroid hormones. continued. The methylene blue sulfide test is a convenient method often used in soil microbiology to quickly detect in water the metabolic activity of sulfate reducing bacteria (SRB). Dec 8, 2023 · The starch pushes the iodine into a line in the middle of the amylose coils and creates a transfer of charge between the iodine and starch. At the point when treated with IKI solution, iodine broke up in a watery arrangement of potassium iodide the tri-iodide-anion edifices with starch, creating a serious blue/purple coloring. Several iodine compounds are used as contrast mediums in diagnostic radiology. Other forms of thyroid problems, namely iodine-induced hypothyroidism species in the blue amylose-iodine complex [23]. The starch solution serves as an indicator of the end of the reaction, forming a deep-blue colored starch–iodine complex in the presence of iodine versus toluidine blue in diagnosing dysplastic changes in tobacco‑associated oral lesions. Find other TSC Stores: Find. It works by mixing the oxidizing agent with iodide ions, which causes iodine to be released. The order of reagents in the Gram stain reaction is: crystal violet, alcohol, iodine, safranin. Iodine is less reactive compared to other halogens and forms compounds with different elements. Iodine forms compounds with many elements, but it is less reactive than the other halogens, which will displace it. A demonstration of this reaction is shown in the video below. 0A, a 5 ~ wide central cavity and 6 glucoses per turn [5-8]. From our R&D, Iodine is one of the biggest biofortifiers to any crop at just 1 PPM. Easy to prepare. The starch forms a blue color when it reacts with iodine. 5 Toluidine blue. Why are iodine and methylene blue used when making the slides? It prevents the slide from drying out when it’s being examined. Tuna is an accessible The iodine clock reaction is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. In this reaction, potassium iodate and sodium meta-bisulfite react to form iodine. The blue color reappears on cooling due to the recovery of iodine binding capacity due to regaining of the helical structure. Boasts powerful antioxidant and Sep 26, 2022 · Chlorella supplies 2. Add a pinch of starch and mix well with a rod. Iodine is an indicator that turns blue-black in the presence of starch. Tuna. e. Sep 29, 2020 · The current study was conducted to evaluate the diagnostic efficacy of acetic acid (2%) (AA), lugol’s iodine (3% dilution) (LIS), and toluidine blue (1%) (TBS) in oral leukoplakia (OL) and Argyria or argyrosis is a condition caused by excessive exposure to chemical compounds of the element silver, or to silver dust. Expand. The sample turns blue-black in color when a few drops of potassium iodide solution are placed on the sample. chemistryviews. The ability to record the time at which the. Starch consists of linear and helical amylose chains (10–20%) and branched amylopectin (80–90%) ( Fig. Jan 30, 2024 · The nature of the blue color in the iodine–starch reaction (or, in most cases, iodine–iodide-starch reaction, i. 0 mcg of iodine. The hypoiodite disproportionates to iodate and iodide. Tuna is an accessible Dec 19, 2020 · A deep blue-black pellet forms when iodine and starch solutions are combined. The absorbance maximum of the iodine-iodide-starch complex in the experiments reported in Supporting Information is at ~580 nm. When the thiosulphate is exhausted (by reaction with the iodine produced), the dark blue iodine-starch complex is formed. Solutions A (iodate) and B (bisulfite) are mixed at room temperature in differing concentrations, producing a blue-black starch/iodine complex after a length of time that depends on the concentrations of reactants. Objectives 1. The cavity provides enough space to accommodate iodine atoms. The photocatalytic performance was studied for methylene blue degradation. The present investigation aimed at identifying the effectiveness of a local desert plant characteristic of Southwest Algeria and known as Salsolavermiculata, which was pyrolyzed and treated chemically with a 50% zinc chloride solution, to remove methylene blue and iodine. com. Mix a solution of hydrogen peroxide with potassium iodide, starch and sodium thiosulfate to see a colourless solution suddenly turn dark blue. It is important to note that an iodine Reaction Kinetics: The Iodine Clock Reaction Introduction The “clock reaction” is a reaction famous for its dramatic colorless-to-blue color change, and is often used in chemistry courses to explore the rate at which reactions take place. A small amount of iodine is essential for nutrition, while too much is toxic. This gland helps to regulate growth and body temperature. It also helps to distinguish between mono– or disaccharides from polysaccharides (glycogen, dextrin, and amylase). Iodine, chemical element, a member of the halogen elements, or Group 17 (Group Iodine dissolves in oleum to make a bright blue solution of I 2 + and sulfur dioxide. Be careful in handling Jul 16, 2021 · 8. By the way, you can also re­peat this ex­per­i­ment in oth­er ways, for ex­am­ple, add one drop of io­dine to a small mound of starch, and a dark blue patch will ap­pear. (The thyroid is a gland in the neck that makes key hormones. Negative Result: No observable color change on addition of iodine solution. More at http://www. , I2 as well as I− are typically present) has for decades elicited debate. . Warning. crystal violet, iodine, alcohol, safranin. Generalized argyria affects large areas over much of the visible surface Jul 9, 2020 · Binding of iodine with amylose leads to the formation of deep-blue complexes, while binding with amylopectin results in a reddish-brown color formation. If you suspect your dog has ingested iodine, it is crucial to contact your veterinarian right away. For example, a gram of spirulina supplies about 5. However, it is now generally accepted that iodide ions are also required in the process, so that the poly-iodine chains inside the amylose helix consist of a mixture/combination of I2 and I-[1–5,24] with an unusual metallic-like structure [25]. Foods that contain iodine include dairy, seaweed, as well as certain fish, beans, and fruit. Here are facts about this interesting, colorful element. The measurement of iodine serves as an index of adequate dietary intake and iodine overload, particularly from iodine-containing drugs such as Amiodarone. Our bodies contain up to 20 milligrams, mainly in the thyroid gland. The color change occurs when I2. In aqueous solution even minute amounts of iodine in the presence of starch produce a blue-black color. Excess I3- is a brown color in solution, and together this produces the dark blue/black color. Oct 2, 2016 · The iodine test is utilized to test for the presence of starch. Once the supply of HSO3- is exhausted, I3- persists in solution and reacts with starch molecules to form a dark blue starch-iodine complex. Thus, the char becomes an attractive by product, thus, attracting the interest of many researchers. 03-0. Your thyroid gland needs iodine to produce May 2, 2024 · On heating, the blue color amylase-iodine complex dissociates but is formed again on cooling because the helical structure is disrupted; thereby amylose loses its iodine binding capacity and the blue color. Dec 22, 2023 · Summary. This indicates that starch is absent in the solution. Nonetheless, it is useful as an adjunct to Lugol's Key words : Methylene Blue, Iodine number, Surface area, Activated carbon properties usually lead to high reactivity, an hence, an alternative usage of char as an adsorbent material become possible. It is a godsend for every per Jan 1, 2024 · Signs of iodine toxicity in dogs may include vomiting, diarrhea, increased thirst, difficulty breathing, or even seizures. Mar 14, 2019 · Iodine is an essential nutrient that can support brain development and reduce your risk for thyroid disease. Only the latter produces the blue complex with iodine which, therefore, is more adequately described as amylose-iodine. in chemistry courses to explore the rate at which reactions take place. Iodine is only slightly soluble in water, although Sep 26, 2023 · A dark blue/black color develops when iodine solution is added to starch solution. 1 Indications. Iodine, with atomic symbol I, is a nonmetal that lies in group 17 of the periodic table, the halogens. Explantion for the incorrect Option: Option(A):Protein. Although Betadine contains iodine, it does not provide iodine supplementation necessary for thyroid function. Jan 1, 2000 · The nature of the blue color in the iodine-starch reaction is still a matter of debate. Rate equation Sep 18, 2023 · Spirulina is a type of blue-green algae that grows in both salt and fresh water. Hence, the given Option is an incorrect one. The radioactive isotope iodine-131 is sometimes used to treat cancerous thyroid glands. To both solutions I added a bit of starch. Matt Meadows/Getty Images. Addition of Iodine to sample turns it to blue in color indicating presence of a) Starch Explanation: Cellulose …. 21 Flinn cientific nc All Rihts Resee. 1%) in comparison to the red reacting (hemiamyloid) substance, which is recognizable only above ca. methylene blue, alcohol, safranin. The iodine clock reaction (in which iodine also serves as a test for starch, forming a dark blue complex), is a popular educational demonstration experiment and example of a seemingly oscillating reaction (it is only the concentration of an intermediate product that oscillates). 2% iodine. The manner in which contiguous chains of such Jun 16, 2022 · Iodine test is a test for detecting the presence of starch. Apr 2, 2021 · The blue colour of starch produced by an iodine solution or iodine reaction is used for its identification. 0 A pitch with an outer diameter of 13. Iodine - KI Reagent: Iodine is not very soluble in water, therefore the iodine reagent is made by dissolving iodine in water in the presence of potassium iodide. The natural plant adsorption capacities were respectively 23mg/g and Only the latter produces the blue complex with iodine which, therefore, is more adequately described as amylose-iodine. For more information on BlueGold® IO-PURE, please call us at 1-307-275-7010or email office@edenbluegold. Each 2 oz bottle of lugol's solution contains approximately 1200 vertical drops of Iodine/iodide. Does Blue-Green Algae Have Iodine in It? Blue-green algae have iodine in them. Nov 26, 2022 · Health Benefits. Some textbooks still invoke charge-transfer bands within a chain of neutral I2 molecules inside the The reaction between iodate and bisulfite in acid medium produces iodine. Open at 8:00 am. May 13, 2023 · Cellulose does not form blue colour with Iodine because it does not contain complex helices and hence cannot hold iodine molecules. Conclusion Our BlueGold® IO-PURE (Iodine) may be used in the biofortification of plants by means of soil and foliar applications. The intensity of the color suggests a clear charge-transfer nature of the band at ~600 nm, and there is consensus regarding the fact that the hydrophobic interior of the amylose helix is the location What to expect. Iodine clock reaction demonstration. Question 21 А B Which one of the above pictures represents a Gram-negative cell? May 12, 2024 · Iodine test. Reduced work productivity. Iodine Element on the periodic table. Boasts powerful antioxidant and Oct 21, 2014 · To increase the effectiveness of your upcoming radioactive iodine therapy, you may be prescribed a low iodine diet. Case report: In a cardiovascular catheterization laboratory invasive hemodynamic monitoring was used to document the lifesaving effect of IV bolus injections of 1. Iodine was used as a dopant to enhance the photocatalytic efficiency. Oct 1, 2023 · The current study studied the synthesis and characterization of iodine-doped Magnetic GO (I-Fe 3 O 4-GO) composite. It has an irritating odor as well. Sep 18, 2023 · Spirulina is a type of blue-green algae that grows in both salt and fresh water. Mar 3, 2000 · — In the darkblue amylose-polyiodide complex, the hydrophobic channel of the single-helical V H-form serves as a well-ordered matrix for incorporation and alignment of the iodine-iodide species to elaborate a linear polyiodide chain in a nearly perfect steric fit and in full complementarity of hydrophobic regions of guest and host. So the solution turned from yellowish to dark blue (if I remember correctly!). Dec 1, 2023 · Iodometric titration is a method used to measure the amount of an oxidizing agent in a solution. Iodine is a weaker oxidizing agent than bromine, chlorine, or fluorine. 5-2 mg/Kg methylene blue solution to treat three patients for anaphylactic shock Dec 1, 2023 · Iodometric titration is a method used to measure the amount of an oxidizing agent in a solution. It is an enhanced form of natural iodine solution that has been used in some medical tests, such as the Lugol’s iodine test for thyroid function, but also as a natural remedy to boost A Flash of Blue. May 7, 2019 · Iodine is a violet vapor or blue-black solid. Iodine Clock (slow motion) - Periodic Dec 11, 2013 · We explored the interaction of iodine with three crystalline type starches, corn, potato, and sweet potato starches using atomic force microscopy. Aug 10, 2023 · the iodine does not turn the starch black. However, at 17 mcg per 3 oz. In this complex, amylose forms a helical structure of 8. This cation is also made when iodine reacts with antimony pentafluoride. As it is absorbed by nucleic acids, toluidine blue stains malignant or dysplastic lesions with elevated mitotic activity. Limitation of Iodine Test. Protein does not give a blue-black color with Iodine. Jul 28, 2019 · When in solution, starch and iodine turn a dark blue color. Iodine is used in the care and feeding of animals and as a stabilizer and/or safety element in food processing. Recommended foliar pairings: Silica. Increased occurrence of hypothyroidism in moderate-to-severe iodine deficiency; decreased occurrence of hypothyroidism in mild-to-moderate iodine deficiency. from publication: Physicochemical properties of porous activated carbon prepared from palm Positive Result: The color of the solution changes to blue-black on addition of iodine. 1 milligrams of iodide. As a re­sult will be a dark blue so­lu­tion. The element iodine lies below bromine, above astatine, to the right of tellurium, and to the left of xenon. The color change occurs when I2 reacts with starch to form a dark blue iodine/starch complex. alarm varies from clock reaction to clock reaction. It is highly nutritious and a great source of protein, copper, and B vitamins. A single injection of radioiodine (also known as I-131) can completely cure hyperthyroidism in cats. Nov 21, 2013 · Iodine is important for a person's thyroid to function normally. Clinical Significance. In this test, iodine and starch form a distinct blue-black colored complex. Sep 8, 2021 · Available to everyone. Sep 8, 2008 · Blue Iodine? Thread starter JSC; Bullied Blue Cochin head split open, deep gash. Feline hyperthyroidism may be caused by an iodine deficiency. The structure of the clathration of the iodine molecules inside trigonal and hexagonal helical channels of the crystal lattice shows a marked similarity with the well-known starch-I2 system, and thus may provide insight for the yet unresolvedructure of the I2 in the helical starch channel. Amylose in starch is responsible for the formation of a deep blue color in the presence of iodine. The leaf that was in the light turns blue-black, which demonstrates that the leaf has been performing photosynthesis and producing starch. Dec 19, 2020 · A deep blue-black pellet forms when iodine and starch solutions are combined. Iodine has an electronegativity of 2. Maximal absorbance of iodine bound to amylopectin is between 500–560 nm, and that for iodine bound to amylose is above 580 nm [158,159]. org/details/video/10619610/Why_Does_Iodine_Turn_Starch_Blue. Collect blood in a royal blue top (trace element) tube with no preservative (serum). During the reaction, two clear liquids are mixed, resulting in another clear liquid. Sep 5, 2017 · An explanation of the common experiment. Feb 1, 2023 · Iodine is an essential mineral you must get from your diet. Dec 16, 2022 · Iodine-iodide mixtures do yield a blue color, which is not observed with glucose instead of starch. Povidone-iodine is a broad spectrum antiseptic for topical application in the treatment and prevention of wound infection. Betadine (povidone-iodine) is an antiseptic solution used to disinfect open wounds or cuts and to prepare the skin for surgery. Iodine is an element you encounter in iodized salt and some dyes. 2. 0 mcg of iodine per gram which is around 40% of the concentration in spirulina. Please enter valid Zipcode, City or State. Option(B):Oil Pour wa­ter into the test tube and add 4-5 drops of io­dine. ) It is found in small amounts in other foods, including saltwater fish Aug 31, 2016 · Today, this complex, or molecular bond, is more commonly referred to as amylose-iodine. Jul 20, 2014 · In this prospective study, which was carried out from March to September, 2013, we have evaluated the performance of iodine-glycerol in comparison to lactophenol cotton blue (LPCB) and Congo-red formaldehyde as an alternative method for identification of filamentous fungi. Make My TSC Store Details. 1. "The iodine clock reaction is based around the colour change that occurs when iodine reacts with starch, turning from a clear colour to a black-blue The purpose of the study was to determine if toluidine blue application and counter staining with Logul's iodine would aid in diagnosis of oral dysplastic or malignant lesions. Methylene blue – stains animal cells to make nuclei more visible. ChickenLord33; Mar 15, 2024; Emergencies / Diseases / Injuries and Cures; Replies 6 Iodine forms a blue complex with starch, and this color test is used to detect small amounts of iodine. It relies on the reaction between iodine and specific compounds, producing a distinct color change. Molecular iodine is not soluble in water, so Potassium iodide is added to it which together forms a polyiodide complex that upon addition of Starch turns intense blue-black color. serving, it is still a decent source of the mineral. Requirements. 7 ). Starch–iodine is dark blue in color because the amylose–iodine complex has an absorption maximum at λ max = 650 nm and because iodine affinity is 20% That a color change takes place at all originates from the fact that the blue reacting (euamyloid) substance has a higher affinity to iodine, and therefore gets stained at a considerably lower iodine concentration (about 0. Its aqueous chemistry is similar to bromine’s. The Iodine Test is a simple yet effective chemical method used to detect the presence of starch and other substances. Then, after a period of several seconds, the solution turns dark blue. Collection. The iodine clock reaction is a favorite demonstration reaction in chemistry classes that usually requires toxic or hazardous chemicals. Cyanobacteria like spirulina contain trace iodine amounts. Using an iodine solution, you can test for the presence of starch. To test the diagnostic efficacy of chemiluminescence Biology. 01-0. The electron affinity of the iodine atom is not much different from those of the other halogen atoms. Introduce your students to rates of reaction and kinetics with the iodine ‘clock’ reaction. The Fourier transform infrared (FT-IR) spectroscopy was carried out to investigate the chemical structure of I-BOC and confirm the modification of β-CD on the surface of I-BOC. Iodine stain can be used to stain plant cells to make the internal structures more visible. Polysaccharides with a reduced degree of polymerization, known as dextrins, are produced in the starch’s partial acid hydrolysis. Iodine, Serum/Plasma - Iodine is an essential element that is required for thyroid hormone production. This element is shiny, blue-black, nonmetallic solid, volatizing into a violet-blue gas at room temperature. This causes a change in the arrangement of electrons and energy level spacings. You can Download scientific diagram | Experimental results for methylene blue (MB) and iodine (I 2 ) adsorption. Question 4 1 pts If addition of iodine to a sample turns it blue then it indicates the presence of O starch O cellulose both a and b Question 5 1 pts Where does starch digestion begin in the human body? O mouth stomach. Using iodine in or near the eyes, ears, or on open Sep 18, 2020 · As soon as all of the S2O3 2- ions are consumed, the excess iodine produced in (5) is free to react with starch, turning the solution blue (7). Learn how this discovery can lead to new materials for solar power and electronics. Now according to wikipedia starch and iodine indeed form a structure Jul 3, 2019 · Iodine is a lustrous blue-black solid which volatizes at room temperature into a violet-blue gas with an irritating odor. After some time, the solution suddenly turns dark blue. The iodine molecule slips inside of the amylose coil. Aug 15, 2020 · I3- is immediately reduced back to I- by any remaining HSO3-. [1] The most dramatic symptom of argyria is that the skin turns blue or blue-gray. The iodine clock reaction is a favorite demonstration in chemistry classes because it has an element of drama. The sensitivity, specificity, and predictive values were studied. 0. TLDR. safranin, alcohol, methylene blue, iodine. The amylose in starch forms helices where iodine molecules assemble, forming a May 21, 2024 · It is also used in investigations to trace the course of compounds in metabolism. 513 Nolan DRSmyrna, TN 37167. (615) 459-0225. Povidone-iodine exhibits longer lasting antiseptic effects than tincture of iodine, due to its slow absorption via soft tissue, making it the choice Iodine is slightly soluble in water and gives a yellow solution. Two clear solutions are mixed, producing a new clear solution. This demonstration can be used at secondary level as an introduction Key words : Methylene Blue, Iodine number, Surface area, Activated carbon properties usually lead to high reactivity, an hence, an alternative usage of char as an adsorbent material become possible. The highest sources (and those to be avoided) are iodized salt, grains and cereals, some breads Jul 16, 2021 · 8. When injected, most of the radioiodine accumulates in the thyroid, while the rest is eliminated in your cat’s urine and feces. As I remember this resulted in a colourchange. Royal blue (trace element) and/or Metal-Free aliquot tubes are available from MLabs (800-862-7284). 3 mg/g) was the sample Oct 6, 2021 · An iodine deficiency can cause a rough coat, apathy, and goiter, which is an enlargement of the thyroid. Jul 27, 2023 · Blue iodine is not a specific chemical compound, but rather a term used to describe the color change that occurs when iodine solution is added to starch. Here are 10 uses of iodine, plus side effects and recommendations for daily intake. This color change occurs due to the formation of a starch-iodine complex, where the iodine molecules interact Feb 1, 2024 · Hence, the appropriate doping of iodine ions not only boosted the visible-light absorption region but played a key role in the modulation of band gap structure. In kittens, a deficiency in iodine can cause a failure to grow, skeletal deformities, skin lesions, and dysfunctions of the nervous system. Iodine also possesses some properties typical of metals. Feb 28, 2023 · Iodine Clock. Many different food groups contain a carbohydrate known as starch. This test helps to identify the presence of starch in a sample. Potassium persulphate is used to oxidize iodide ions to iodine, in the presence of starch and a small amount of thiosulphate ions. Lastly, it is important to note that iodine is for external use only. Allow specimen to clot for 30 minutes, centrifuge, and carefully pour serum into a metal-free aliquot tube, avoiding transfer of the cellular Nov 1, 2008 · The maximum sorption capacity toward iodine (1180 mg/g) was found for the white-rice-based activated carbon, whereas the most effective in the methylene blue removal (221. Iodine is often used to test foods for starch. Iodine reacts with nitric acid and chlorates to make iodates, too. Toxic nodular goiter; iodine-induced hyperthyroidism. Iodine is element 53 on the periodic table, with element symbol I. It must be noted that in this colorimetric test, methylene blue is a product formed by the reaction and not a reagent added to the system. Background: The purpose of this paper is to propose methylene blue as a lifesaving alternative drug for the treatment of contrast-induced anaphylaxis. html Chemical Test for Starch or Iodine. This composite was then used for application in wastewater treatment. Because tuna is a fattier fish than other varieties, it contains less iodine. Impaired mental function. Therefore, it may be found in varying amounts in all food and beverages. The iodine test is primarily specific to starch. To know when the reaction is complete, we use starch solution as an indicator. What Wudl and Seshadri found is that the blue/black color is produced from the linear structure of iodine polymer chains, created in the presence of either amylose or pyrroloperylene, an organic semiconductor, interacting with photons of light. Iodine’s most important role is to ensure proper thyroid function. Results revealed that starch molecules aggregated through interaction with iodine solution as well as iodine vapor. Thus, the Adults. This indicates that starch is present in the solution. The reaction is called a clock reaction because the amount of time Jan 18, 2018 · The Iodine and potassium iodide used in Naples Naturals lugol's solution is derived from natural salt brine deposits 2 Miles beneath the surface, in the western United States. Starch–iodine is dark blue in color because the amylose–iodine complex has an absorption maximum at λ max = 650 nm and because iodine affinity is 20% Apr 17, 2020 · Both contained iodine $\ce{I2}$ as a solute. Aug 23, 2016 · How does starch turn iodine dark blue? UCSB scientists discovered the first observation of crystalline infinite iodide polymers, a rare phenomenon in chemistry. Biology questions and answers. When starch is present, the iodine changes from brown to blue-black or purple. [1] The iodine clock reaction exists in several variations, which each involve iodine species ( iodide ion, free iodine, or iodate ion) and redox reagents in the presence of May 7, 2019 · Iodine is a violet vapor or blue-black solid. 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