Sodium chloride (table salt) is commonly made through the neutralization reaction of sodium hydroxide with hydrochloric acid.
Here's a more detailed breakdown:
Neutralization Reaction
-
Reactants: Sodium hydroxide (NaOH), a strong base, and hydrochloric acid (HCl), a strong acid.
-
Process: When these two chemicals are combined in the correct proportions, they neutralize each other.
-
Products: The reaction produces sodium chloride (NaCl) and water (H₂O).
-
Equation: The chemical equation for this reaction is:
NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)
Laboratory Method: Titration
In a laboratory setting, a common method to carry out this reaction is titration. This allows for precise control over the amounts of reactants used:
- Preparation: A known volume of sodium hydroxide (NaOH) solution of a known concentration is placed into a flask. A few drops of an indicator, such as phenolphthalein, are added. Phenolphthalein is pink in basic solutions but colorless in neutral or acidic solutions.
- Titration: Hydrochloric acid (HCl) of a known concentration is slowly added from a burette into the flask containing the sodium hydroxide.
- Endpoint: The hydrochloric acid is added until the pink color of the phenolphthalein disappears, indicating that the solution has reached the neutralization point (all the sodium hydroxide has reacted with the hydrochloric acid).
- Evaporation: The resulting solution, which contains sodium chloride and water, is then heated to evaporate the water, leaving behind solid sodium chloride.
Industrial Production
Industrially, sodium chloride is primarily obtained from two main sources:
- Mining: Rock salt deposits, formed from the evaporation of ancient seas, are mined. The mined salt is then processed and purified.
- Evaporation of Seawater: Seawater is evaporated in large shallow ponds. As the water evaporates, the salt crystallizes out and is then collected and processed.
Summary
In summary, sodium chloride can be created in a lab through a neutralization reaction between sodium hydroxide and hydrochloric acid, carefully controlled via titration. Industrially, it is predominantly obtained through mining rock salt or evaporating seawater.
