To make a saturated sodium chloride solution, you prepare a mixture where the maximum amount of salt has dissolved in the water, with some undissolved salt remaining, indicating that the solution has reached its saturation point.
Understanding Saturated Solutions
A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent at a given temperature. At this point, any additional solute added will not dissolve and will typically settle at the bottom, creating a dynamic equilibrium between the dissolved and undissolved states.
Step-by-Step Preparation
According to the provided information, preparing a saturated solution of sodium chloride (NaCl) involves a straightforward process:
- Measure Water: Begin with $100mL$ of water.
- Add Sodium Chloride: Gradually add approximately $40 - 45g$ of sodium chloride to the $100mL$ of water.
- Mix Thoroughly: Stir the mixture vigorously to promote dissolution. You should observe that as you add the salt and stir, some amount of sodium chloride will eventually remain undissolved at the bottom of the container. This undissolved salt is a key indicator that your solution has become saturated.
- Separate the Solution: Once you have confirmed the presence of undissolved salt, allow the mixture to settle. The clear liquid above the undissolved salt is your saturated sodium chloride solution. You can then obtain this pure saturated solution by filtration (pouring the mixture through a filter to separate the solid salt from the liquid) or decantation (carefully pouring off the liquid, leaving the solid behind).
This method ensures that the water has dissolved as much sodium chloride as it possibly can at room temperature.
Key Components for Saturated NaCl Solution
The essential quantities for preparing a saturated sodium chloride solution are summarized below:
| Component | Quantity (Approximate) |
|---|---|
| Sodium Chloride (NaCl) | $40 - 45g$ |
| Water | $100mL$ |
Practical Considerations
- Stirring is Crucial: Continuous and vigorous stirring will help the salt dissolve more quickly and efficiently, ensuring the solution reaches saturation faster.
- Witnessing Undissolved Salt: The presence of undissolved salt is the definitive sign that your solution is saturated. If all the salt dissolves, add a little more until a small amount remains at the bottom.
- Temperature Effects: While the provided quantities are for a general preparation (typically implying room temperature), the solubility of sodium chloride in water does slightly increase with temperature. However, for a saturated solution, the principle remains the same: add enough salt until no more can dissolve.
Applications of Saturated Sodium Chloride Solution
Saturated sodium chloride solutions, often called brine, are widely used in various fields due to their unique properties:
- Food Preservation: Brine is historically used for pickling vegetables, curing meats, and preserving fish, leveraging salt's ability to inhibit microbial growth.
- Chemical Laboratories: Employed as a reagent, in salt baths for temperature control, or as a dense solution for separation processes.
- Industrial Processes: Utilized in water treatment, as a drilling fluid in the oil and gas industry, and in the production of chlorine and sodium hydroxide.
