Instructional Period 3: PREPARATION AND
STANDARDIZATION OF ~0.10 M SODIUM HYDROXIDE
SOLUTION
OBJECTIVE
Prepare ~0.10 M aqueous solution by diluting a concentrated
solution.
Standardize the diluted solution via titration to determine its accurate
concentration.
INTRODUCTION
The standardization of solution is carried out via titration using potassium
hydrogen phthalate as the primary standard. A primary standard usually exhibits
the following properties:
1. It must be prepared, purified, dried and stored easily.
2. It must be stable and not absorb water when weighed.
3. The reaction with a primary standard must be fast and complete within an
acceptable time frame.
Solid cannot be used as a primary standard owing to its hygroscopic
property, i.e. it has the ability to attract and hold water molecules from
surrounding environment. also reacts with carbon dioxide in the air. The
standardized solution will be used as a secondary standard in the
subsequent experiments.
Dilution is a process by which water or any other suitable solvent is added to a
concentrated solution of known volume and molarity. As a result, the volume of
the dilute solution is now larger, and the molarity of the diluted solution is
inversely smaller compared to molarity of the concentrated solution.
It is extremely important that you take steps to work safely by following lab
instructions and general lab rules and also, learn and use good titration skills
which will be useful in other titration experiments you will perform later in this
course.
In this experiment, as well as others, the accuracy of your measurements and
correct calculations are extremely important aspects of your laboratory training
and education.
The CHEM162 Lab Manual by Ruyi Qi, Andrew Bolig, and Kevin Worden is licensed
under the Creative Commons Attribution 4.0 International License (CC-BY 4.0).
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