Sodium Iodide Lab Report

“The iodine clock reaction was discovered by the Swiss chemist Hans Heinrich Landolt in 1886.” (Scilearn, 2017). There are many variations of the iodine clock reaction but they all involve two colourless solutions being mixed and after a specific period of time, the mixed solutions turn dark blue. The iodate variation of the clock reaction involves the reaction between iodate ions. These being, IO3-, hydrogen sulfite ions, HSO3-, and hydronium ions, H+. To ensure the blue colour change, starch is needed to be added to the solution, reacting with I2. The delay in colour change occurs because as soon as I2 is formed, it immediately reacts with any HSO3- still present and is converted into colourless I-. After all the HSO3- has been consumed, the concentration of the I2 increases and begins reacting with the starch. This is why the dark blue colour is suddenly present. The reaction of the starch reacting to turn the solution a deep blue colour. The reaction occurs in two steps. The first step generates iodide ion (I in Equation 2, which occurs slowly and is the rate determining step. “A rate determining reaction is the slowest step in a reaction mechanism and is assumed to be equal to the overall reaction rate because the reaction cannot go faster than the slowest step.”(Webcache.googleusercontent.com, 2017 ).

Title: The Effect Temperature of Sodium Thiosulfate Has On The Rate of Reaction with Hydrochloric Acid

The first step that needed to be done in this experiment was adding hydrochloric acid (HCl)

The rate of a chemical reaction often depends on reactant concentrations, temperature, and if there’s presence of a catalyst. The rate of reaction for this experiment can be determined by analyzing the amount of iodine (I2) formed. Two chemical reactions are useful to determining

Purpose: The purpose of this experiment is to use kinetics to study a solvolyis reaction

The compound was tested for the presence of ammonium, carbonate, sulfate, chloride, and nitrate, as seen in Table 2. The nitrate test produced a precipitate, indicating the presence of the nitrate ion in the compound. At this point it was hypothesized that our unknown compound was calcium nitrate.

Therefore Iodine can be utilized to detect the presence of starch since the reaction of I2+ I- gives us I3 - . What this means is that any substance that becomes blue/black after iodine has been added to it proves that the substance has starch in it. Interestingly enough, when Iodine is added either to white rice or sweet potatoes, these two foods turn to the blue black color that confirms the presence of starch. However, If I add iodine to a banana, it only turns yellow which confirms that the banana does not contain iodine.

In this lab we performed four test. Using these test we discovered how the chemicals compounds Citric Acid, Calcium Chloride, Sucrose, Potassium Iodine, Phenyl Salicylate , and Sodium Chloride reacted to heat and many solutions. We also noticed that Phenyl salicylate was the least reactive out of all chemical compounds. Using the information discovered from the lab we were able to separate the chemical compounds into two groups. In group one were the chemical compounds Calcium chloride, Citric acid, Potassium iodide, Sodium chloride, and Sucrose these chemical compounds reacted to three of the four test. Group two was just Phenyl salicylate which reacted to only one of the four test. We also were able to state that group one was a covalent compound group and, group two was an ionic compound

To see if the concentration of hydrochloric acid will increase the rate of the reaction between magnesium ribbon and hydrochloric acid.

0.300 grams of biphenyl/ p-toluidine sample was weighed. Next, 10 mL of dichloromethane was measured in a graduated cylinder. The dichloromethane was transferred to a small beaker then the solid mixture was dissolved in it. A Thin Layer Chromatography (TLC) was conducted with the dissolved mixture in 20% Ethyl Acetate and 80% Hexane solution. The TLC plate was observed to be impure with two spots. To being extraction, a separatory funnel was placed inside of the hood and the stopcock was closed. A flask was placed under the funnel then the mixture was added to the funnel. Next, 10 mL of 3M HCL was measured in a graduated cylinder and

The purpose of this lab was to find out how gaviscon reacted with different salt solutions. Sodium Alginate is a compound that forms with the Gaviscon and forms a “raft” and blocks all the stomach acid from traveling up the esophagus.

These equations can only be carried out and be visible after the iodine has completely reacted with thiosulphate added – two moles of thiosulphate for every mole of iodine. Once all the thiosulphate has been used up in the reaction, the colour will start to appear.

"Iodine Clock" refers to a group of reactions which involve the mixing of two colorless solutions to produce a solution which gives rise to an initial induction period, before a sudden change creates a deep purple-blue color (http://web.mst.edu/~gbert/IClock/discussion.htm)

4) Try and propose a mechanism for the reaction using the orders of reaction taking into account the iodine, propanone and sulphuric acid.

The procedure was performed as follows: For run 1, 20cm3 of acetone, 10cm3 of sulphuric acid and 145cm3 of water was added to a conical flask. 25cm3 of iodine was then added to this solution which started the reaction and immediately, 20cm3