Find ph of a mix formed by mixing 2 volumes. Solution A has vol 300ml and ph 7Solution B has vol 700ml and ph 5

To find the pH of a mixture formed by combining two solutions, we can use the concept of hydrogen ion concentration. Each solution contributes to the overall concentration of hydrogen ions in the mixture, which ultimately determines the pH. Let's break this down step by step.

Understanding the Components

We have two solutions:

• Solution A: 300 mL with a pH of 7
• Solution B: 700 mL with a pH of 5

Calculating Hydrogen Ion Concentrations

The pH scale is logarithmic, meaning each whole number change on the scale represents a tenfold change in hydrogen ion concentration. The formula to find the hydrogen ion concentration \([H^+]\) from pH is:

[H⁺] = 10^-pH

Now, let's calculate the hydrogen ion concentrations for both solutions:

• For Solution A (pH 7):

[H⁺] = 10^-7 = 1 x 10^-7 M

• For Solution B (pH 5):

[H⁺] = 10^-5 = 1 x 10^-5 M

Calculating Total Moles of Hydrogen Ions

Next, we need to find the total moles of hydrogen ions contributed by each solution. To do this, we multiply the concentration of hydrogen ions by the volume of each solution (in liters):

• For Solution A:

Moles of H⁺ = [H⁺] x Volume = (1 x 10^-7 M) x (0.300 L) = 3 x 10^-8 moles

• For Solution B:

Moles of H⁺ = [H⁺] x Volume = (1 x 10^-5 M) x (0.700 L) = 7 x 10^-6 moles

Finding Total Moles and Volume of the Mixture

Now, we can add the moles of hydrogen ions from both solutions:

Total moles of H⁺ = (3 x 10^-8) + (7 x 10^-6) = 7.03 x 10^-6 moles

The total volume of the mixture is:

Total Volume = 300 mL + 700 mL = 1000 mL = 1 L

Calculating the Final Concentration of Hydrogen Ions

Now, we can find the final concentration of hydrogen ions in the mixture:

[H⁺] = Total moles of H⁺ / Total Volume = (7.03 x 10^-6 moles) / (1 L) = 7.03 x 10^-6 M

Determining the Final pH

Finally, we can convert this concentration back to pH using the formula:

pH = -log[H⁺]

pH = -log(7.03 x 10^-6) ≈ 5.15

Final Result

The pH of the mixture formed by combining 300 mL of Solution A (pH 7) and 700 mL of Solution B (pH 5) is approximately 5.15.