An experiment is carried out to determine the rate constant, k, for the hydrolysis of ethyl ethanoate, CH3COOC2H5, using a hydrochloric acid, HCl(aq), catalyst. The equation for the reaction is shown. H⁺ CH3COOC2H5 + H2O → CH3COOH + C2H5OH The rate equation for this reaction is shown. rate of reaction = k [CH3COOC2H5] The progress of the reaction is followed by determining how the concentration of acid changes with time. A portion of the reaction mixture is removed every 5 minutes and titrated with sodium hydroxide, NaOH(aq). A final titration is carried out after 180 minutes. A student carries out the following steps. step 1 Add 70cm³ of iced water to seven separate small conical flasks. Add a few drops of phenolphthalein indicator to each flask. Phenolphthalein is pink in alkaline conditions and colourless in acidic conditions. step 2 Use a measuring cylinder to transfer 100cm³ of 0.200 moldm⁻³ HCl(aq) into a large conical flask. step 3 Add 5.00 cm³ of CH3COOC2H5 to the large conical flask and swirl the flask to mix the contents. Start a stopwatch. step 4 Transfer 10.00cm³ of reaction mixture to one of the small conical flasks containing the iced water and indicator. Record the time. Shake the small flask. step 5 Carry out a single titration of the mixture in the small conical flask using 0.15moldm⁻³ NaOH(aq). step 6 Repeat steps 4 and 5 at the times shown in Table 2.1 using a different small conical flask for each titration.