Introduction

Phosphoric acid, H?PO?, is a strong acid widely used in various applications. The determination of the number of {H}^{ } ions in a given mass of H?PO? is crucial for understanding its acidic properties. This article aims to provide a detailed step-by-step guide on finding the number of {H}^{ } ions in 9.8g of H?PO?, following the principles of chemical stoichiometry and physical chemistry.

Understanding Phosphoric Acid: H?PO?

Phosphoric acid is a weak organic acid that ionizes in water to produce {H}^{ } ions and H?PO?? ions, with a structure that can accommodate further ionization steps. The primary ionization can be represented as:

H?PO? H?O ? H?PO?? H?O?

This reaction shows that each molecule of H?PO? produces one {H}^{ } ion per molecule ionized in water.

Step-by-Step Calculation: Finding the Number of {H}^{ } Ions in 9.8g of H?PO?

To find the number of {H}^{ } ions in 9.8g of H?PO?, we need to follow these steps:

Calculate the Molar Mass of H?PO?: Determine the Number of Moles of H?PO?: Calculate the Number of {H}^{ } Ions: Convert Moles of {H}^{ } Ions to Number of Ions:

1. Calculate the Molar Mass of H?PO?

Let's start by calculating the molar mass of H?PO?:

H: 1.01 g/mol × 3 3.03 g/mol P: 30.97 g/mol O: 16.00 g/mol × 4 64.00 g/mol

Total molar mass 3.03 30.97 64.00 98.00 g/mol

2. Determine the Number of Moles of H?PO?

Now, we convert the given mass of H?PO? (9.8g) to moles:

Moles of H?PO? mass / molar mass

Moles of H?PO? 9.8 g / 98.00 g/mol 0.1 mol

3. Calculate the Number of {H}? Ions

Each molecule of H?PO? can release up to 3 {H}^{ } ions. Therefore, we can calculate the total number of {H}^{ } ions:

Total {H}^{ } ions moles of H?PO? × 3 (since each H?PO? can produce 3 {H}^{ } ions)

Total {H}^{ } ions 0.1 mol × 3 0.3 mol {H}^{ } ions

4. Convert Moles of {H}^{ } Ions to Number of Ions

To find the total number of {H}^{ } ions, we use Avogadro's number (6.022 × 1023 ions/mol):

Number of {H}^{ } ions moles × Avogadro's number

Number of {H}^{ } ions 0.3 mol × 6.022 × 1023 ions/mol ≈ 1.81 × 1023 {H}^{ } ions

Conclusion

The number of {H}^{ } ions in 9.8g of H?PO? is approximately 1.81 × 1023 ions. This calculation is based on the basic stoichiometric principles and shows the process of converting mass to moles, then to the number of ions.

Note: In a dilute aqueous solution, the actual number of {H}^{ } ions can be influenced by various factors, such as ionization constants, pH, and the presence of other species. Therefore, this calculation assumes a dilute solution where {H}^{ } ions are in the form of the conjugate acid produced by H?PO? in water.

References

For further reading, consider the following references:

Ionization of Phosphoric Acid in Aqueous Solution Basic Ionization Constants of Phosphoric Acid