Submitted by Iris Olaso
______________________________________________________________________________
INTRODUCTION
Generally, there are two ways in preparing a solution, one is by dissolving a weighed amount of solid in a required solvent and the other is by dilution of a concentrated solution into the desired concentration.
In diluting concentrated solution, the concentration of the diluted solution can be determined by standardization. To standardize a solution, we will need to perform titration. In this experiment, we will standardize acid and base solutions.
In this experiment, the students to students will be able to know the proper way of preparing solutions from solid and liquid reagents by using the proper pieces of glassware and equipment and to calculate the exact concentration of the prepared solution from standardization.
PROCEDURE
The reagents that were used in this experiment were concentrated hydrochloric acid, sodium hyrdoxide, sodium carbonate, potassium acid phthalate and phenolphthalein as indicator.
The pieces of glassware that were used to perform this experiment were volumetric flasks, Erlenmeyer flasks, beakers, volumetric pipette, burette, spatula and droppers. Also, the pieces of equipment that were used were analytical balance, top-loading balance and hot plate.
Preparation of 250 mL 1.0 M sodium hydroxide solution (from solid)
The amount of NaOH needed to prepare 1.0M solution was calculated (10.0 g NaOH). The computed value was weighed using the top-loading balance and placed in a clean and dry 250-mL beaker. Enough amount of distilled water to dissolve the NaOH solid was added to the beaker and stirred. After the NaOH was completely dissolved, the solution was then transferred to a 250-mL volumetric flask quantitatively. Enough distilled water was added to make the volume about 200-mL. The flask was covered and cooled down to room temperature. The
References: G. D. Christian, Analytical Chemistry, 6th Edition, John Wiley & Sons, New York, Chapter 8 and 2 D. Harvey, Modern Analytical Chemistry, Mc-Graw Hill, USA, p. 274 Skoog, etal. ,Fundamentalsof AnalyticalChemistry, Eighth edition, 2004, p. 338-340