1. a. What is the titrant for this experiment? b. Is the indicator generally added to the titrant or the analyte in a titration? 2. a. What is the primary standard used in this experiment (name and formula)? Define a primary standard. b. What is the secondary standard used in this experiment (name and formula)? Define a secondary standard. 3. Distinguish between a stoichiometric point and an endpoint in an acid-base titration. 4. a. When rinsing a buret after cleaning it with soap and water, should the rinse be dispensed through the buret tip or the top opening of the buret? Explain. 16 b. Experimental Procedure, Part A.4. In preparing the buret for titration, the final rinse is with the NaOH titrant rather than with deionized water. Explain. 5. Part A.3. Calculate the mass of KHC,H,O, (molar mass=204.23 g/mol) that reacts with 15 mL of the 0.15 M NaOH solution prepared in Part A.2. Express this mass KHC,H,O, to the correct number of significant figures and record the calculation on the Report Sheet. Experiment 9 139 6. a. Complete the following table of Trial 1 (See Report Sheet.) for determining the molar concentration of a standard NaOH solution, followed by the determination of the molar concentration of a monoprotic acid solution according to the experimental procedure. Record calculated values with the correct number of significant figures. A. Standardization of a Sodium Hydroxide Solution 1. Tared mass of KHC,H,O, (e) 2. Molar mass of KHC,H,O, (g/mol) 3. Moles of KHC,H,O, (mol) Show calculation. 4. Buret reading, initial (mL) 5. Buret reading, final (ml) Calculation Zone 0411 204.44 Part A.3 4.20 19.90 6. Volume of NaOH dispensed (mL) Part A.7 7. Molar concentration of NaOH solution (mol/L) Show calculation. B. Molar Concentration of an Acid Solution 1. Volume of acid solution (m.) Part B.6 25.0 2. Buret reading, initial (mL) 3.70 3. Buret reading, final (ml) 20.47 4. Volume of NaOH dispensed (mL) 5. Molar concentration of NaOH solution (mol/L) Part B.7 6. Moles of NaOH dispensed (mol) Show calculation. 7. Molar concentration of acid solution (mol/L) Show calculation. 6. b. For Trials 2 and 3, the molar concentration of the acid was 0.0922 M and 0.0856 M respectively. a. What is the average molar concentration of the acid solution? Data Analysis, B. b. What are the standard deviation and the relative standard deviation (%RSD) for the molar concentration of the acid solution? Data Analysis, C and D. 140 A Volumetric Analysis