Determining the pH of a Nitric Acid Solution
Understanding the pH of a solution is crucial for many applications, from water treatment to laboratory experiments. This article will guide you through calculating the pH of a 7602 mL solution containing 1.2 grams of nitric acid (HNO3).
Concepts and Terminology
The pH of a solution is a measure of the concentration of hydronium ions ([H3O ]) and is defined by the equation:
pH -log[H3O ]
Nitric acid (HNO3) is a strong acid, which means it dissociates completely in water to produce hydronium ions and nitrate ions:
HNO3 H2O → H3O NO3-
Therefore, for every mole of HNO3 that dissociates, one mole of H3O is produced.
Calculation Steps
Convert the mass of nitric acid to moles:Given: 1.2 grams of Nitric acid
Molar mass of HNO3 63.01 g/mol
Calculating moles:
1.2 g HNO3 × (1 mole HNO3 / 63.01 g HNO3) 0.019 moles HNO3
Convert volume from milliliters to liters:Given: 7602 mL of solution
7602 mL × (1 L / 1000 mL) 7.602 L
Calculate the molarity of nitric acid:Molarity (M) is defined as:
M moles of solute / liters of solution
Molarity of HNO3 0.019 moles / 7.602 L 0.0025 M
Therefore, the concentration of H3O is also 0.0025 M.
Calculate the pH of the solution:Using the pH equation:
pH -log[H3O ]
pH -log(0.0025) ≈ 2.6
Conclusion
By following these steps, we determined that the pH of a 7602 mL solution containing 1.2 grams of nitric acid is 2.6. This calculation is essential for both educational and practical applications, ensuring that the solution's acidity is accurately understood.