TitrationsEasy Medium Difficult Solutions to these questions can be found here. 1) What mass of Hydrochloric acid would need to be weighed out to be added to a 250mL volume of water in a volumetric flask such that the concentration of the solution was 0.10M? 2) What is the difference between the equivalence point and the end point of a reaction? 3) Which indicator is the most appropriate choice to measure the end-point of the following titration experiments? a) Sodium hydroxide and sulfuric acid b) Hydrochloric acid and potassium hydroxide c) Acetic acid and ammonium hydroxide 4) If 15.48mL of a 0.015M aqueous HCl solution is required to titrate 20.0mL of aqueous NaOH to the equivalence point, what is the molarity of the NaOH solution? 5) Sally is doing a titration experiment to calculate the concentration of acetic acid in the vinegar that she uses for her salad dressing. She takes 10mL of the vinegar and dilutes it in water to make up a volume of 100mL. She then performs a titration on 15.0mL of the resultant solution by titrating it with 12.78mL of 0.10M NaOH. a) What was the original concentration of acetic acid in her salad dressing? b) Sally repeats the experiment 3 times. By doing so, which of the following has she improved upon? A) Validity B) Precision C) Accuracy D) Reliability 6) In a titration of a weak base with a strong acid, both the volumetric flask and the burette were rinsed thoroughly with distilled water. a) Why is this not the correct technique? b) What is the correct technique? c) In what way would the above technique have affected the results of the experiment? 7) What strength of acid and base is the following titration curve reflective of? 8) A titration experiment is conducted to calculate the concentration of NaOH in an unknown solution, using a 0.15M standard solution of HCl. To perform the experiment, 20mL of the NaOH solution is made up to a volume of 100mL. 15mL of the NaOH is reacted with 18.65mL of the HCl to reach the appropriate equivalence point. a) Calculate the concentration of NaOH in the unknown solution. b) Suggest two ways to improve upon the accuracy of the findings in a titration experiment. 9) A 15.0mL sample of vinegar requires 18.15mL of a known standard of 0.10M NaOH to reach the endpoint of a titration reaction. Calculate the concentration of acetic acid in the vinegar.
10) A titration experiment is conducted to confirm the concentration of acetic acid in a sample of vinegar. The student, Bobby, remembers diluting the vinegar by taking 20mL and making up a volume of 250mL to use in his titration. He uses 15.35mL of a known standard of NaOH with 22.60mL of his diluted vinegar and calculates the concentration of acetic acid in his original vinegar sample to be 0.00259M. In a laboratory mixup, he has lost the original concentration of the NaOH standard. He decides that you, as his lab partner, should calculate the value from his lab notes.
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