Titration Basics and Stoichiometry

Questions and Answers

What is the titrant for this experiment?

NaOH

Is the indicator generally added to the titrant or the analyte in a titration?

Analyte (correct)

Titrant

What is the primary standard in this experiment and define primary standard.

Potassium hydrogen phthalate; KHC8H4O4; high purity, large molar mass, nonhygroscopic, reacts in predictable way

What is the secondary standard in this experiment and define secondary standard.

Sodium hydroxide; NaOH; measured amount of moles in a measured amount of solution or its molarity, measured amount of solution reacts with the substance being analyzed. Signup and view all the answers

Distinguish between stoichiometric point and endpoint.

Stoichiometric point is when the mole ratio is reached; endpoint is when the phenolphthalein changes color. Signup and view all the answers

When rinsing the buret after cleaning it with soap and water, should the rinse be dispersed through the buret tip or the top opening of the buret? Explain.

Through the tip because you want to get all the water out since any water left can dilute the solution of the titrant. Signup and view all the answers

Why is the final rinse done with NaOH titrant rather than with deionized water? Explain.

Rinse with the titrant (NaOH) because you want to get any other substances out of the buret so nothing affects the experiment. Signup and view all the answers

Calculate the mass of KHC8H4O4 (molar mass=204.23 g/mol) that reacts with 15 mL of the 0.15 M NaOH solution.

0.4595 g Signup and view all the answers

Study Notes

Titration Basics

Titrant used in the experiment is sodium hydroxide (NaOH).
The indicator is generally added to the analyte, the solution being tested, rather than the titrant.

Standards and Their Definitions

Primary standard: potassium hydrogen phthalate (KHC8H4O4) known for high purity, large molar mass, non-hygroscopic properties, and consistent reactivity.
Secondary standard: sodium hydroxide (NaOH) which is quantified via known moles in a measured solution and reacts with the analyte.

Stoichiometry in Titration

Stoichiometric point is reached when the precise mole ratio of reactants is achieved.
Endpoint is indicated by a color change in phenolphthalein, signaling that the reaction has completed.

Buret Rinsing Techniques

When rinsing a buret post-cleaning, the rinse solution should be sent through the buret tip to ensure all water is expelled, preventing dilution of the titrant.
The final rinse should be conducted with the titrant (NaOH) to remove residual contaminants, ensuring the accuracy of the experiment.

Calculation of Mass in Titration

For 15 mL of 0.15 M NaOH, the moles of NaOH calculated are 0.00225 mol.
This amount corresponds to 0.00225 mol of KHC8H4O4 based on a 1:1 mole ratio.
The mass of KHC8H4O4 is computed as 0.4595 g, calculated using its molar mass of 204.23 g/mol, rounded to the correct number of significant figures.

Description

Test your knowledge on the fundamentals of titration, including the use of sodium hydroxide as a titrant and the importance of various standards. This quiz covers concepts like stoichiometric points and the proper techniques for rinsing a buret.