Acid/Base Titration Essay Example

patel (rmp932) – Post-Lab 5 Acid/Base Titration – lyon – (51730) This print-out should have 25 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Answer the question to at least six significant figures. A solution of sodium hydroxide is standardized against potassium hydrogen phthalate (KHP, formula weight 204.2 g/mol). From the following data, calculate the molarity of the NaOH solution: mass of KHP 1.404 g; buret reading before titration 0.13 mL; buret reading after titration 38.57 mL. Answer in units of M 002 10.0 points What is the main objective of Part 1 of the experimental procedure? What is the purpose of using KHP in this part of the experiment? 1. The main purpose of Part 1 is to gain practice doing titrations before we titrate our unknown acid in Part 2. KHP is used in Part 1 because we don’t want to use up our unknown acid during the practice titrations, and KHP is an inexpensive alternative to a real acid. 2. The main objective of Part 1 is to determine the concentration of the NaOH solution as accurately and precisely as possible. KHP is used as a titration standard because it is very pure, and can therefore yield highly accurate results for the NaOH concentration. 3. The main objective of Part 1 is to verify the color change of the phenolphthalein at the endpoint of the titration, since we will be relying on phenolphthalein in Part 2 and don’t want to use it without verification. KHP is used because it is colorless when dissolved in water, and therefore does not interfere with the color change of the phenolphthalein. 4. The main objective Part 1 is to determine the purity of the NaOH solution. We can determine the percent purity of the NaOH

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solution by taking a mole ratio of NaOH to KHP. 5. The main objective of Part 1 is to make sure all the students are paying attention to standard laboratory safety practices before they receive a vial of acid to work with. KHP is