(Solved):   CHE 362 PRACTICAL 2 TITLE: REACTION KINETICS OF A NUCLEOPHILIC REACTION AIM: To establish ...

 

CHE 362 PRACTICAL 2 TITLE: REACTION KINETICS OF A NUCLEOPHILIC REACTION AIM: To establish whether the reaction of methyl iodide with hydroxide ion is second order or first order Safety Measure 1. Wear gloves before handling chemicals as \( \mathrm{CH}_{3} \) I is very toxic 2. Pipetting must be done with a pipette filler Main steps 1. Preparation of a \( 50 \mathrm{~mL} 2.0 \mathrm{M} \mathrm{KOH} / \) aqueous ethanol/ \( \mathrm{CH}_{3} \) l solution mixture 2. Stabilisation of the temperature on the water bath 3. Followed by immediate withdrawal of \( 1.0 \mathrm{~mL} \) of the solution and titrating it with \( 0.1 \mathrm{M} \) \( \mathrm{HCl} \) at different time intervals Scheme of reaction 1. Nucleophilic reaction: \( \mathrm{CH}_{3} \mathrm{I}+\mathrm{KOH} \rightarrow \mathrm{CH}_{3} \mathrm{OH}+\mathrm{KI} \) 2. Back titration reaction: \( \mathrm{KOH}+\mathrm{HCl} \rightarrow \mathrm{H}_{2} \mathrm{O}+\mathrm{KCl} \) Procedure 6.2 \( \mathrm{mL} \) of methyl iodide were measured into a clean dry \( 50 \mathrm{~mL} \) volumetric flask, and made up to the mark with equilibrated \( \mathrm{KOH} / \) aqueous ethanol solution. The contents of the flask were mixed thoroughly before the flask was suspended on the water bath. Timing was started as soon as the reactants were mixed. \( 1.0 \mathrm{~mL} \) aliquot was withdrawn immediately after mixing the reagents and the same was done at \( \mathrm{t}=6,12,22,32,42,52 \) minutes. For each particular \( 1.0 \mathrm{~mL}, 25 \mathrm{~mL} \) distilled water and a few drops of phenolphthalein indicator were added and then titrated against \( 0.1 \mathrm{M} \mathrm{HCl} \). The whole procedure was carried out at \( 24^{\circ} \mathrm{C} \). Initial concentrations of the reagents: CALCULATIONS AND DATA ANALYSIS 1. Using the volumes of \( \mathrm{HCl} \) used in titration at different time intervals. Calculate the concentrations of \( \mathrm{CH}_{3} \mathrm{I} \) and \( \mathrm{KOH} \) at those time intervals. 2. By applying the integrated rate laws of reaction kinetics, determine the order of reaction between \( \mathrm{CH}_{3} \) I and \( \mathrm{KOH} \) DATA COLLECTED At \( t=0 \), Volume of \( \mathrm{HCl} \) used \( =20.0 \mathrm{~mL} \)