The specific gravity of a sodium bicarbonate solution is not a single, fixed value; it depends on the concentration of sodium bicarbonate dissolved in the water. However, the reference provided points to a value more commonly associated with the solid form of sodium bicarbonate.
Understanding the Provided Reference
The reference states: Specific Gravity: 2.16 g/cm³.
It is crucial to clarify this information:
- Specific gravity is a dimensionless ratio. It compares the density of a substance to the density of a reference substance (usually water at 4°C, which has a density of 1 g/cm³ or 1 g/mL). Therefore, specific gravity itself does not have units.
- The value 2.16 g/cm³ is widely recognized as the density of solid sodium bicarbonate (NaHCO₃), also known as baking soda.
Specific Gravity of Solid Sodium Bicarbonate
Based on the provided reference value for density, we can determine the specific gravity of solid sodium bicarbonate:
Density and Specific Gravity Comparison
| Property | Value | Units | Notes |
|---|---|---|---|
| Density of Solid Sodium Bicarbonate | 2.16 | g/cm³ | As indicated by the reference (though labeled "Specific Gravity") |
| Density of Water (reference substance) | 1.00 | g/cm³ | At 4°C, the standard reference for specific gravity |
| Specific Gravity of Solid Sodium Bicarbonate | 2.16 | (unitless) | Calculated as (Density of Solid NaHCO₃) / (Density of Water) = 2.16 / 1.00 |
Therefore, if the intent was to provide the specific gravity of solid sodium bicarbonate based on its density, the value is 2.16.
Specific Gravity of Sodium Bicarbonate Solutions
The specific gravity of an actual sodium bicarbonate solution will be considerably lower than that of the solid compound and will vary with the concentration of sodium bicarbonate dissolved in the water. Since a solution is primarily water, its specific gravity will be slightly greater than 1.0 (the specific gravity of pure water).
Examples of Solution Specific Gravity
- Dilute solutions: For very dilute solutions, the specific gravity will be very close to 1.0, similar to pure water.
- Concentrated solutions: As more sodium bicarbonate is dissolved, the specific gravity increases.
- A typical saturated sodium bicarbonate solution at room temperature (e.g., 20°C) generally has a specific gravity in the range of approximately 1.05 to 1.10.
- For instance, a 10% (w/w) sodium bicarbonate solution has a specific gravity of roughly 1.07.
Practical Insights
- Manufacturing and Quality Control: In industrial processes, specific gravity measurements are crucial for monitoring the concentration of sodium bicarbonate solutions, ensuring consistency in product formulation (e.g., in antacids, baking, or cleaning products).
- Laboratory Applications: Scientists use specific gravity to prepare solutions of precise concentrations or to quickly estimate the concentration of an unknown solution.
