Properties:
White crystalline powder
Odorless
Soluble in water
Slightly alkaline taste
Decomposes at high temperatures
Chemical formula: NaHCO₃
Preparation (Solvay Process):
Prepared industrially by passing carbon dioxide and ammonia through a concentrated sodium chloride (brine) solution.
Chemical Reaction:
"NaCl"+〖"NH" 〗_3+〖"CO" 〗_2+"H" _2"O" →〖"NaHCO" 〗_3+〖"NH" 〗_4"Cl"
Sodium bicarbonate precipitates out and is then filtered, washed, and dried.
Uses:
As a systemic antacid to treat acid indigestion, heartburn, and upset stomach.
As a leavening agent in baking.
As an odor neutralizer and cleaning agent.
In the management of metabolic acidosis and certain drug overdoses (under medical supervision).
Assay (Acid-Base Titration):
Prepare a Standard Solution: Dissolve a known amount of a strong acid, such as hydrochloric acid (HCl), in water to create a solution with a known concentration.
Sample Preparation: Weigh an accurate amount of NaHCO₃ and dissolve it in water.
Add Indicator: Add a pH indicator, such as phenolphthalein, to the NaHCO₃ solution. The indicator changes color at neutralization.
Titrate: Slowly add the standard HCl solution to the NaHCO₃ solution while stirring. NaHCO₃ reacts with HCl, forming water, carbon dioxide (CO₂), and sodium chloride (NaCl). The endpoint is reached when the indicator changes color.
Calculate Concentration: Measure the volume of HCl used in the titration to calculate the concentration or purity of NaHCO₃.