Lab 8 Titration

Suppose you are titrating an acid of unknown concentration with a standardized base. At the beginning of the titration, you read the base titrant volume as 1.52 mL. After running the titration and reaching the endpoint, you read the base titrant volume as 21.63 mL. What volume, in mL, of base was required for the titration?

20.11 mL

What appearance of an acidic analyte solution containing phenolphthalein indicates the endpoint of titration with a basic solution?

A persistent pale pink color throughout the solution.

What practice will NOT help you make an accurate volume reading on a burette at the beginning of a titration?

Make sure that the meniscus starts exactly at 0.00 mL.

How can you improve your ability to see the indicator color change at the endpoint of a titration?

Place a piece of white paper under the analyte flask throughout the titration.

When filling a burette for a titration, adjust the burette so that check_circle_outline, preferably over a sink. Then, check_circle_outline to add the titrant into the burette. The titrant should be filled check_circle_outline.

When filling a burette for a titration, adjust the burette so that the opening is near or below eye level, preferably over a sink. Then, use a funnel to add the titrant into the burette. The titrant should be filled almost to the zero mark.

Suppose you are titrating a sulfuric acid solution of unknown concentration with a sodium hydroxide solution according to the equation H2SO4+2NaOH⟶2H2O+Na2SO4 If you require 30.40 mL of 0.924 M NaOH solution to titrate 213.1 mL of H2SO4 solution, what is the concentration of the H2SO4 solution?

0.0659

How many grams of KOH are needed to neutralize 12.6 mL of 0.14 M HCl in stomach acid?

0.099

Suppose you are titrating vinegar, which is an acetic acid solution of unknown concentration, with a sodium hydroxide solution according to the equation HC2H3O2+NaOH⟶H2O+NaC2H3O2 If you require 34.63 mL of 0.1496 M NaOH solution to titrate 10.0 mL of HC2H3O2 solution, what is the molar concentration of acetic acid in the vinegar?

0.518

Calculate the mass percent of a vinegar solution with a total mass of 98.38 g that contains 3.72 g of acetic acid. Type answer:

3.78

Suppose you are titrating an acid solution with a base solution of known concentration. To calculate the concentration of the acid solution, use three steps. 1. Use the check_circle_outline of base check_circle_outline the endpoint and the known concentration of the base solution to find the check_circle_outline of base used. 2. Use the check_circle_outline to find the moles of acid from the moles of base. 3. Divide the moles of acid by the volume of check_circle_outline the titration to find the concentration of acid.

Suppose you are titrating an acid solution with a base solution of known concentration. To calculate the concentration of the acid solution, use three steps. 1. Use the delivered volume of base to reach the endpoint and the known concentration of the base solution to find the moles of base used. 2. Use the molar ratio to find the moles of acid from the moles of base. 3. Divide the moles of acid by the volume of acid solution before the titration to find the concentration of acid.

Before running a titration, you calculate the expected endpoint. However, when performing the experiment, you pass the expected endpoint with no visible color change. What is the most likely problem with the titration set-up?

There is not enough indicator in the analyte.