28 Feb 2012 Rate Law Determination LC CHE 169 of the Crystal Violet Exp.#A 11 Reaction In this experiment, it will study the reaction between crystal violet and sodium hydroxide. One objective is to study the relationship between concentration of crystal violet and the time elapsed during the reaction. The equation for the reaction is shown here. (CH3)2 N(CH302 oHT N(CH3)2 NOCH302 A simplified (and less intimidating!) version ofthe equation is cv (aq)+ OH (aq) CvoH (aq) (crystal viole) (hydroxide) The rate law for this reaction is in the form is the where k is the rate constant for the reaction, m is the order with respect to crystal violet (Cv and n order with respect to the hydroxide ion. Because the hydroxide ion concentration is more than 1000 times as large as the concentration of crystal to DOH will not change during experiment. Thus, you find the order with respect crystal violet (m), but the order with respect to (n). As the reaction proceeds a violet-colored reactant will be slowly changing to a colorles You will measure the color change with a Vemierspectrometer. The crystal solution used in it the appropriate this experiment absorbance spectrum of the solution. We will assume that proportional on crystal violet Beer's law). Absorbance will be used in place to the concentration of graphs: of concentration in plotting the three Absorbance vs. time: A linear plot indicates a zero order reaction (k--slope) In Absorbance vs. time: A linear plot indicates a first order reaction (k -slope) 1/Absorbance vs. time: A linear plot indicates order reaction (k slope). Once the order with respect to crystal violet has been determined, you will also be finding the rate constant, k, and the halflife for this reaction.