Question

In the reaction between bleach and dye, the bleach was in significant excess relative to the dye.

Select all that are True.
If bleach and dye had similar concentrations, we could not have used graphs to determine the orders.
Because bleach is in such large excess, changing its concentration will have no impact on the rate of the reaction.
You can find the order with respect to the bleach by graphing different versions of its concentration vs. time.
Undiluted bleach is best "light" reference for calibrating the spectrometer for the reaction.
To find the order with respect to the bleach, we could have had the dye in significant excess and used the same experimental setup.

Answer 1

The statements that are true are:

Because bleach is in such large excess, changing its concentration will have no impact on the rate of the reaction.

since the concentration of bleach is in large excess over the other component, slight change in concentration of the bleach will not have an impact on the reaction rate which will become independent of the concentration of bleach. Thus the reaction will become pseudo zero order with respect to the bleach.

You can find the order with respect to the bleach by graphing different versions of its concentration vs. time

Monitoring the absorbance change with time one can obtain a plot of change in concentration as a function of time. From the plot one can determine the order of a reaction.

Undiluted bleach is best "light" reference for calibrating the spectrometer for the reaction

The reaction mixture contains bleach and the dye. The dye and ts complex is responsible for the absorption of light while the bleach should ideally have no absorbance in the region of wavelength concerned. Any absorbance of the bleach would possibly arise due to the presence of contaminants and this fact should be taken into account when measuring absorbance of the mixture. Thus undiluted bleach could be used to collect background soectrum and calibrate the spectrometer.