Question

Information regarding the question:

Concentration of NaOH=0.05138 M

Concentration of Crystal Violet Dye Solution=0.001 M

Room Temperature=25 degree Celcius

Absorbance from the device- spectrovis(spectrophotometer)

Time: Trial 1 Trial 2

0 0.089 0.430

30 0.106    0.323

60 0.121    0.248

90 0.106    0.187

120 0.063 0.141

150 0.045 0.109

180 0.028 0.082

210 0.023 0.060

240 0.014 0.045

270 0.010 0.036

300 0.005 0.027

330 0.003 0.017

360 0.000 0.015

390 -0.001 0.008

420 -0.002 0.006

450 -0.002 0.007

The following calculations must be handwritten in your notebook. – Conversion of %Transmittance to Absorbance ■ Only one handwritten sample is necessary ■ However, all of your %Transmittance values must be converted to Absorbance in your Data Table

–The steps you took to determine the order with respect to the Crystal Violet Dye (X in the example)

– The steps you took to determine the order with respect to the NaOH (Y in the example)

– The steps you took to determine k – The overall, Modified Rate Law ■ With your values for X, Y, and k inserted into the equation

– Solve the Rate Law ■ Insert in all values necessary Result

Answer 1

Absorbance is proportional to the concentration of crystal violet (A = εl[CV+]) and can be used instead of concentration when plotting data (A ≈ [CV+]).

This reaction can be represented as- CV+ + OH- → CVOH

k [CV]x [OH- ] y

First, you will vary the concentration of hydroxide, [OH- ], allowing determination of y in equation (2). As a second step, you will determine x in equation RATE equation.

Because this reaction has two reactants and is likely to follow a complicated mechanism, the reaction orders may not be simple whole numbers.