0.1 N Phosphoric Acid Preparation
Introduction
Phosphoric acid is a strong acid widely used in various industries, including food, fertilizer, and pharmaceuticals. In laboratory settings, phosphoric acid is used as a reagent for various analytical and preparative purposes. In this article, we will discuss the preparation of 0.1 N phosphoric acid, a commonly used concentration in laboratory settings.
Materials
- Phosphoric acid (H3PO4) 85% w/w
- Distilled water
- Volumetric flask (1 L)
- Balance
- Pipettes
Preparation
Step 1: Calculate the required amount of phosphoric acid
To prepare 0.1 N phosphoric acid, we need to calculate the required amount of phosphoric acid needed. The normality of phosphoric acid is defined as the number of equivalents of phosphoric acid per liter of solution. Since phosphoric acid is a tribasic acid, one mole of phosphoric acid is equivalent to three moles of hydroxide ions. Therefore, the normality of phosphoric acid can be calculated as follows:
Normality (N) = Number of equivalents / Liter of solution = 3 x Molarity (M) = 3 x (moles of phosphoric acid / Liter of solution)
For 0.1 N phosphoric acid, we need to calculate the moles of phosphoric acid required:
Moles of phosphoric acid = Normality x Liter of solution / 3 = 0.1 x 1 L / 3 = 0.0333 moles
Step 2: Weigh the required amount of phosphoric acid
Using a balance, weigh the required amount of phosphoric acid:
Mass of phosphoric acid = Moles of phosphoric acid x Molar mass = 0.0333 moles x 97.97 g/mol = 3.26 g
Step 3: Dissolve the phosphoric acid in distilled water
Transfer the weighed phosphoric acid to a 1 L volumetric flask and add a small amount of distilled water to dissolve the acid.
Step 4: Dilute the solution to the mark
Add distilled water to the flask until the mark, making sure to mix the solution thoroughly.
Verify the Normality
To verify the normality of the prepared phosphoric acid solution, you can perform a titration with a strong base such as sodium hydroxide (NaOH).
Conclusion
In this article, we have discussed the preparation of 0.1 N phosphoric acid, a commonly used concentration in laboratory settings. By following the steps outlined above, you can accurately prepare 0.1 N phosphoric acid for your laboratory needs. Remember to handle phosphoric acid with care, as it is corrosive and can cause skin and eye irritation.
