produce iodide ion (I-) and dehydroascorbic acid‚ as shown in the following equation: [IMAGE] + I2(aq) -----------> + 2H+(aq) + 2I-(aq) Ascorbic acid (Vit. C) Dehydroascorbic acid However‚ since iodine is only slightly soluble in water‚ ascorgic acid should not be titrated directly by a standard iodine solution‚ since the end point of titration is not o obvious. Instead‚ back titration will be employed. The titration of a reducing agent with iodine to produce iodide ion is
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There are three reactions in the iodine clock reaction. The first reaction is IO3-(aq) + 3 HSO3-3 SO4-(aq) + I-(aq)+ 3 H+(aq)‚ where the iodate ions become iodide ions1. The second reaction is 6 H+(aq) +IO3-(aq) + 5 I-(aq) 3 I2(aq) + 3 H2O(l) where the iodate ions become molecular iodine2. The third reaction involves molecular iodine becoming a dark blue starch;I2(aq) + starch blue-black complex3. These three reactions react in a sequence. In any reaction the concentration is exponentially related
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William son Eth er Synth esis Introduction In this reaction‚ an alcohol is deprotonated to form a good nucleophile‚ which then attacks the electrophile methyl iodide to form an ether. Tetrabutylammonium bromide‚ a phase transfer catalyst‚ is used to carry ions back and forth between the organic phase and the aqueous phase. OH O NaOH + NaI + H2O CH3I Before coming to lab‚ please review the following techniques: "Reluxing a reaction‚" "Extraction and washing‚" "Drying an Organic Solvent‚" "Evaporating
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done by forming triiodide ions. To make the measurement more accurate‚ starch was added to help determine the endpoint of the solution. The significance of this lab is that industry can use these techniques to determine the amount of NaClO in the bleach of the rival industry and improve it. Hypothesis: The hypothesis is that‚ an accurate determination of NaClO in commercial bleach can be done. By mixing the acidified iodide ion to the hypochlorite solution‚ the iodide is oxidized to iodine which
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CH 125 INORGANIC CHEMISTRY FOR MICROBIOLOGY Laboratory Manual 2013 Edition By Brian Clark‚ Marco Castillo & Patrick Chan CENTENNIAL COLLEGE OF APPLIED ARTS & TECHNOLOGY‚ SCARBOROUGH‚ ONTARIO Preliminary Laboratory Information - CH 125 The following safety information is provided to the student in order to ensure that all students and college staff working in the laboratory are aware of common industrial laboratory safety practices. Laboratory
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the electrodes. What is electrolysis? Ionic substances contain charged particles called ions. For example‚ lead bromide contains positively charged lead ions and negatively charged bromide ions. Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them. For electrolysis to work‚ the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or when melted. For example
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Antioxidant Concept: Vitamin C (ascorbic acid) is an antioxidant. The amount of vitamin C content in food can be found out by titrating with an oxidising agent‚ e.g. iodine. In the reaction‚ vitamin C is oxidised‚ while iodine is reduced to iodide ions. The endpoint is determined by the formation of blue-black starch-iodine complex when all vitamin C is oxidised and excess iodine is free to react with the starch solution added as indicator. Introduction Vitamin C is an important component of
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by Potassium Iodide Brief Description: Two solutions are mixed resulting in an eruption of foam resembling a huge stream of toothpaste. This is the classic “Elephant Toothpaste” reaction. Purpose/Goal: Procedure presents an example of a catalyzed reaction. Explanation of Experiment: The rapid evolution of oxygen gas is produced by the following reaction: 2 H2O2 (aq) = 2 H2O (l) + O2 (g) + heat The decomposition of hydrogen peroxide in the presence of iodide ion occurs in two
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protons‚ 44 neutrons‚ 35 electrons (1) 81Br 35 protons‚ 46 neutrons‚ 35 electrons (1) 2 (iii) (1s2)2s22p63s23p63d104s24p5 (1) 1 [4] 2. (i) iodide has been converted to iodine (1) (with correct use and spelling of iodide and iodine) The 1st experiment shows that bromine is more reactive than iodine (1) The 2nd experiment shows that chlorine is more reactive than bromine (1) Accept 1 mark for 2nd and 3rd marking points if the
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Synthesis of Phenols You can prepare phenols in large quantities by the pyrolysis of the sodium salt of benzene sulfonic acid‚ by the Dow process‚ and by the air oxidation of cumene. Each of these processes is described below. You can also prepare small amounts of phenol by the peroxide oxidation of phenylboronic acid and the hydrolysis of diazonium salts. Pyrolysis of sodium benzene sulfonate In this process‚ benzene sulfonic acid is reacted with aqueous sodium hydroxide. The resulting salt
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