For example‚ adults need about 150 micrograms of iodine in the form of iodide ion per day. However‚ an insufficient supply of iodide via diet and drinking water causes the non-cancerous enlargement of the thyroid gland known as goiter. Prolonged lack of iodide can lead to loss of thyroid function and the birth defect known as cretinism‚ which has been recognized since the Middle Ages. Iodide ion‚ in the form of potassium iodide‚ may be added to table salt to produce "iodized salt" in order to easily
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redox titration. The method used is iodine-thiosulfate titration. It is a very useful method‚ since the iodide ion‚ I-‚ is easily oxidized by almost any oxidizing agent. The analysis takes place in a series of steps as follows: 1. A diluted sample of the bleach will be allowed to react with potassium iodide in acidic solution. The iodide ion will be oxidized to iodine while the hypochlorite ion will be reduced to chloride (Equation 1). 2 H+(aq) + OCl-(aq) + 2 I-(aq) ! Cl-(aq) + I2(aq) + H2O(l)
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1210 Laboratory Manual. Vol. 2013-2014. Plymouth: Hayden-McNeil. 32-35. Data/Results: Part A: In the potassium iodide solution‚ I think there were potassium atoms as well as iodine atoms. In the lead nitrate solution‚ I think there were lead and nitrate ions. The potassium atoms and the lead atoms can be classified as cations‚ since they are metals. The iodine atoms and the nitrate ion can be classified as anions since they are nonmetals. Upon mixing‚ the solution turned into a cloudy yellow color
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When ionic solids dissolve‚ they divide to give their positive and negative ions that make up the solids. These ions become hydrates and have the same relative proportions when in solution and when solid. The more the solid dissolves‚ the more the ion’s concentration increases. This increase and build-up allows for the reverse reaction to occur. In this phase of the reaction the ions crystallise out in order for the reaction to have a greater chance of occurring. Eventually the rate of
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the effect of varying the concentration of iodide ions on the rate of reaction between hydrogen peroxide and an acidified solution of potassium iodide: H2O2(aq) + 2H+(aq) + 2I⁻ → 2H2O(l) + I2(aq) The course of this reaction can be followed by carrying it out in the presence of small quantities of starch and sodium thiosulfate solutions. As the iodine molecules are produced they immediately react with the thiosulfate ions and are converted back to iodide ions: I2(aq) + 2S2O32⁻(aq) → 2I⁻(aq) + S4O62⁻(aq)
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important for plant fertilizers since potassium helps plant growth. The metal halides form white ionic crystalline solids. They are all soluble in water except LiF because of a high lattice enthalpy due to the electrostatic attraction between Li+ and F- ions. All halogens are quite reactive‚ and in the natural world they always occur combined with other elements. Fluorine reacts so readily with almost any substance it contacts that chemists were not successful in isolating pure fluorine until. Chlorine
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iodometry‚ where iodine “is produced in-situ from the quantitative oxidation of iodide and then subsequently titrated with thiosulfate solution‚”2 being the difference from the former type of iodine titration. Iodometry is more widely used‚ as in this experiment‚ because there are only a few strong reducing agents; thus few iodometric determinations. (2) As mentioned earlier‚ iodometry involves the oxidation of iodide ion; it is added in excess to the oxidizing agent being determined. This would result
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References: Heitz.‚ M(2005) General Chemistry: An Integrated Approach‚ Chapter 16: More Equilibria in Aqueous Solutions: Slightly Soluble Salts and Complex Ions‚ 4th Edition‚ Prentice Hall‚ Inc.‚ State University of New York. pp. 715-718 Housecroft‚ C.E. & Constable‚ E.C. (2006)‚ Introduction to spectroscopy‚ in Chemistry‚ 3rd Edition‚ Pearson Education‚ England. pp. 951-970 Silberberg‚ M.S. (2006)‚ Chemistry:
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throughout the procedure are outlined below: Mn2+ + 2OH– + 1/2 O2 oxygen-manganese complex + H2O (1) oxygen-manganese complex + 4H+ + 2I– I2 + Mn2+ + 2H2O (2) I2 + 2Na2S2O3 Na2S4O6 + 2NaI (3) Addition of the manganous sulfate and the alkaline-iodide results in the formation of an insoluble oxygen-manganese complex (1)‚ the precipitate in step 2. The oxygen is stable in this form for several days. Both the
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halogen atom becomes a halide ion. | | | | Some typical nucleophiles are the hydroxy group (−OH)‚ the alkoxy group (RO−)‚ and the cyanide ion (−C N). Reaction of these nucleophiles with an alkyl halide (R—X) gives the following reactions and products: | | | | The halogen ion that is displaced from the carbon atom is called the leaving group‚ and the overall reaction is called a nucleophilic substitution reaction. Procedure: 1. Sodium Iodide in Acetone. Acetone‚ with
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