Question

Explain how the following factors would affect the accuracy or precision of the determination of the rate constant, k, in this experiment. (a) the true molarity of the NaOH is different from that given on the bottle. (b) the tert-butyl chloride contains several percent tert-butyl alcohol as an impurity (c) During the experiment, the room temperature changes by several degrees. (d) The flask is uncorked while the tert-butyl chloride solution is being heated to complete the reaction, so that some of the tert-butyl chloride is lost by evaporation.

Answer 1

Determination of rate constant

(a) If the true molarity of NaOH is different from the given molarity on the bottle : the estimated rate constant would be not accurate. However, running the reaction may give a good precision.

(b) The t-butyl chloride contained t-butyl alcohol : the estimated rate constant would be very different in accuracy but precision may be good as using sample solution for all the runs.

(c) If room temperature changed during experiment : the accuracy and precision both would drastically be different.

(d) If flask is open while heating t-butyl chloride in it : The accuracy and precision would vary as the t-butyl chloride would evaporate during this step.