Hydronium Ion Concentration and pH

Oct 13, 2025 by wbrum.org 58 views

Introduction

In chemistry, pH is a measure of the concentration of hydrogen ions (H+) in a solution. It is a crucial concept in understanding the properties of acids and bases. In this article, we will explore the relationship between hydronium ion concentration, pH, pOH, and hydroxide ion concentration.

Hydronium Ion Concentration and pH

The hydronium ion (H3O+) is a hydrogen ion that has been associated with a water molecule (H2O). It is a measure of the concentration of hydrogen ions in a solution. The pH of a solution is defined as the negative logarithm of the hydronium ion concentration.

pH Formula

The pH formula is given by:

pH = -log[H3O+]

where [H3O+] is the concentration of hydronium ions in moles per liter (M).

Given Hydronium Ion Concentration

We are given that the hydronium ion concentration of a solution is 0.150 M. We can use this value to calculate the pH of the solution.

Calculating pH

Using the pH formula, we can calculate the pH of the solution as follows:

pH = -log(0.150) pH = 0.824

pH Value

The pH value of the solution is 0.824. This means that the solution is acidic, as the pH value is less than 7.

pOH and Hydroxide Ion Concentration

The pOH of a solution is defined as the negative logarithm of the hydroxide ion concentration. The hydroxide ion (OH-) is the conjugate base of the hydronium ion (H3O+).

pOH Formula

The pOH formula is given by:

pOH = -log[OH-]

where [OH-] is the concentration of hydroxide ions in moles per liter (M).

Relationship Between pH and pOH

There is a relationship between pH and pOH that can be expressed as follows:

pH + pOH = 14

Calculating pOH

Using the relationship between pH and pOH, we can calculate the pOH of the solution as follows:

pOH = 14 - pH pOH = 14 - 0.824 pOH = 13.176

pOH Value

The pOH value of the solution is 13.176. This means that the solution is acidic, as the pOH value is greater than 7.

Hydroxide Ion Concentration

Using the pOH formula, we can calculate the hydroxide ion concentration of the solution as follows:

[OH-] = 10^(-pOH) [OH-] = 10^(-13.176) [OH-] = 2.00 x 10^(-14) M

Hydroxide Ion Concentration Value

The hydroxide ion concentration of the solution is 2.00 x 10^(-14) M. This means that the solution is very weakly basic, as the hydroxide ion concentration is very low.

Conclusion

In conclusion, we have calculated the pH, pOH, and hydroxide ion concentration of a solution with a hydronium ion concentration of 0.150 M. The pH value is 0.824, the pOH value is 13.176, and the hydroxide ion concentration is 2.00 x 10^(-14) M. These values indicate that the solution is acidic.

References

Atkins, P. W., & De Paula, J. (2010). Physical chemistry. Oxford University Press.
Brown, T. E., & LeMay, H. E. (2014). Chemistry: The Central Science. Pearson Education.
Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2016). General chemistry: Principles and modern applications. Pearson Education.
Frequently Asked Questions (FAQs) About pH, pOH, and Hydroxide Ion Concentration =====================================================================================

Q: What is the pH of a solution with a hydronium ion concentration of 0.100 M?

A: To calculate the pH of a solution, we use the formula pH = -log[H3O+]. Plugging in the given value, we get pH = -log(0.100) = 1.000.

Q: What is the pOH of a solution with a pH of 4.500?

A: To calculate the pOH of a solution, we use the formula pOH = 14 - pH. Plugging in the given value, we get pOH = 14 - 4.500 = 9.500.

Q: What is the hydroxide ion concentration of a solution with a pOH of 10.200?

A: To calculate the hydroxide ion concentration of a solution, we use the formula [OH-] = 10^(-pOH). Plugging in the given value, we get [OH-] = 10^(-10.200) = 1.26 x 10^(-11) M.

Q: What is the pH of a solution with a hydroxide ion concentration of 5.00 x 10^(-8) M?

A: To calculate the pH of a solution, we first need to calculate the pOH using the formula pOH = -log[OH-]. Plugging in the given value, we get pOH = -log(5.00 x 10^(-8)) = 7.300. Then, we can calculate the pH using the formula pH = 14 - pOH. Plugging in the value, we get pH = 14 - 7.300 = 6.700.

Q: What is the pOH of a solution with a pH of 2.500?

A: To calculate the pOH of a solution, we use the formula pOH = 14 - pH. Plugging in the given value, we get pOH = 14 - 2.500 = 11.500.

Q: What is the hydroxide ion concentration of a solution with a pH of 9.000?

A: To calculate the hydroxide ion concentration of a solution, we first need to calculate the pOH using the formula pOH = 14 - pH. Plugging in the given value, we get pOH = 14 - 9.000 = 5.000. Then, we can calculate the hydroxide ion concentration using the formula [OH-] = 10^(-pOH). Plugging in the value, we get [OH-] = 10^(-5.000) = 1.00 x 10^(-5) M.

Q: What is the pH of a solution with a hydronium ion concentration of 1.00 x 10^(-6) M?

A: To calculate the pH of a solution, we use the formula pH = -log[H3O+]. Plugging in the given value, we get pH = -log(1.00 x 10^(-6)) = 6.000.

Q: What is the pOH of a solution with a hydroxide ion concentration of 1.00 x 10^(-3) M?

A: To calculate the pOH of a solution, we use the formula pOH = -log[OH-]. Plugging in the given value, we get pOH = -log(1.00 x 10^(-3)) = 3.000.

Conclusion

In this article, we have answered some frequently asked questions about pH, pOH, and hydroxide ion concentration. We have used the formulas pH = -log[H3O+], pOH = 14 - pH, and [OH-] = 10^(-pOH) to calculate the pH, pOH, and hydroxide ion concentration of various solutions. We hope that this article has been helpful in understanding these important concepts in chemistry.