Titration- Standardization of a NaOH Solution Flashcards
(13 cards)
The main purpose for the AB1: Standardization of NaOH experiment is to:
Titrate a sodium hydroxide (NaOH) solution of unknown concentration with potassium hydrogen phthalate (or KHP- the primary standard) to determine the true concentration of NaOH (the secondary standard)
In this lab, we will be measuring
pH as a function of volume
The following items will be part of the experimental setup as you collect data over the course of the lab. Select all that apply.
Vernier pH probe
Phenolphthalein
Kim wipe
Stir bar
Vernier Graphical Analysis
Stir plate
Beaker or flask containing dissolved KHP
Burette
Burette clamp
During lab, you will use the dilution equation ____________ when preparing your _____________ M solution of NaOH.
M1V1=M2V2; 0.1
n the colorimetric titration experiment, we expect the indicator, __________ to change from _________ in acidic solutions to ___________ in basic solutions.
phenolphthalein
colorless
pink
The following characteristics define what a primary standard is. Select all that apply.
Stable in air
Dries readily
Soluble in water
Has quantitative reactivity with the substance to be standardized
Has a detectable equivalence point with high accuracy
High in purity
You prepare a solution by dissolving 0.743 g potassium hydrogen phthalate (KHP, 204.221 g/mol) in 25.0 mL of distilled deionized water with 2 drops of phenolphthalein. It takes an addition of 17.33 mL approximately 0.1 M sodium hydroxide (NaOH) stock solution to turn your KHP solution a faint shade of pink. What is the true concentration of [OH-] in your prepared NaOH stock solution?
0.210M
How can a titration curve be defined?
It is a graphical description of the solution pH as a function of the volume of added titrant
Select all that apply: According to the background reading, our analysis will entail
A first derivative plot to confirm the point where moles of acid = moles of base
A titration curve
The inflection point is the greatest change in slope along the acid/base titration curve. The first derivative plot peak:
corresponds to the region of greatest slope, therefore an equivalence point in the titration curve.
Acids may have several equivalence points due to the presence of multiple protons.
True
The proper method to load a burette with solution is:
at eye level (lowering the burette in the sink or acquiring a stool as necessary)
You will store your left-over prepared secondary standard, the NaOH stock solution, for next week’s lab: AB2 Identification of an unknown acid.
True
