4) What Is The Concentration Of H+ Ions In Solution If OH Ion = 0.007m? (kw = 1 × 10-19)
In chemistry, the concentration of hydrogen ions (H+) and hydroxide ions (OH-) in a solution is crucial in determining the solution's pH and pOH. The pH and pOH are related through the water dissociation constant (Kw), which is a measure of the equilibrium between H+ and OH- ions in water. In this article, we will explore the relationship between H+ and OH- ions in a solution and calculate the concentration of H+ ions when the concentration of OH- ions is given.
The Water Dissociation Constant (Kw)
The water dissociation constant (Kw) is a measure of the equilibrium between H+ and OH- ions in water. It is defined as the product of the concentrations of H+ and OH- ions in a solution. The Kw value is temperature-dependent and is typically expressed as 1 × 10^-14 at 25°C. However, in this problem, we are given a Kw value of 1 × 10^-19, which is a much lower value than the typical Kw value.
Calculating the Concentration of H+ Ions
When the concentration of OH- ions is given, we can use the Kw expression to calculate the concentration of H+ ions. The Kw expression is given by:
Kw = [H+][OH-]
where [H+] and [OH-] are the concentrations of H+ and OH- ions, respectively. We are given that [OH-] = 0.007 M. We can rearrange the Kw expression to solve for [H+]:
[H+] = Kw / [OH-]
Substituting the given values, we get:
[H+] = 1 × 10^-19 / 0.007
Solving for [H+]
To solve for [H+], we can divide 1 × 10^-19 by 0.007. This gives us:
[H+] = 1.4286 × 10^-16
Therefore, the concentration of H+ ions in the solution is 1.4286 × 10^-16 M.
Understanding the pH Scale
The pH scale is a measure of the concentration of H+ ions in a solution. It is defined as the negative logarithm of the concentration of H+ ions. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. A pH less than 7 is acidic, while a pH greater than 7 is basic.
Calculating the pH of the Solution
We can calculate the pH of the solution using the concentration of H+ ions we calculated earlier. The pH is given by:
pH = -log[H+]
Substituting the value of [H+], we get:
pH = -log(1.4286 × 10^-16)
Solving for pH
To solve for pH, we can take the negative logarithm of 1.4286 × 10^-16. This gives us:
pH = 15.85
Therefore, the pH of the solution is 15.85.
Conclusion
In this article, we explored the relationship between H+ and OH- ions in a solution and calculated the concentration of H+ ions when the concentration of OH- ions is given. We used the Kw expression to solve for [H+], and then calculated the pH of the solution using the concentration of H+ ions. The pH of the solution was found to be 15.85, indicating that the solution is basic.
References
- Atkins, P. W., & De Paula, J. (2010). Physical chemistry. Oxford University Press.
- Brown, T. E., & LeMay, H. E. (2012). Chemistry: The Central Science. Prentice Hall.
- Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2011). General chemistry: Principles and modern applications. Pearson Education.
Frequently Asked Questions (FAQs) About H+ and OH- Ions ===========================================================
In the previous article, we explored the relationship between H+ and OH- ions in a solution and calculated the concentration of H+ ions when the concentration of OH- ions is given. However, we understand that there may be many questions and doubts that readers may have. In this article, we will address some of the frequently asked questions (FAQs) about H+ and OH- ions.
Q: What is the difference between H+ and OH- ions?
A: H+ ions are positively charged ions, while OH- ions are negatively charged ions. H+ ions are also known as hydrogen ions, while OH- ions are also known as hydroxide ions.
Q: What is the Kw value, and how is it related to H+ and OH- ions?
A: The Kw value is the water dissociation constant, which is a measure of the equilibrium between H+ and OH- ions in water. It is defined as the product of the concentrations of H+ and OH- ions in a solution. The Kw value is typically expressed as 1 × 10^-14 at 25°C.
Q: How do I calculate the concentration of H+ ions when the concentration of OH- ions is given?
A: To calculate the concentration of H+ ions when the concentration of OH- ions is given, you can use the Kw expression:
Kw = [H+][OH-]
where [H+] and [OH-] are the concentrations of H+ and OH- ions, respectively. Rearranging the Kw expression to solve for [H+], we get:
[H+] = Kw / [OH-]
Q: What is the pH scale, and how is it related to H+ ions?
A: The pH scale is a measure of the concentration of H+ ions in a solution. It is defined as the negative logarithm of the concentration of H+ ions. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. A pH less than 7 is acidic, while a pH greater than 7 is basic.
Q: How do I calculate the pH of a solution when the concentration of H+ ions is given?
A: To calculate the pH of a solution when the concentration of H+ ions is given, you can use the pH expression:
pH = -log[H+]
where [H+] is the concentration of H+ ions.
Q: What is the relationship between pH and pOH?
A: The pH and pOH are related through the Kw expression:
Kw = [H+][OH-]
Since pH = -log[H+] and pOH = -log[OH-], we can write:
pH + pOH = 14
Q: Can you provide some examples of how to calculate the concentration of H+ ions and pH?
A: Here are a few examples:
- Example 1: Calculate the concentration of H+ ions when the concentration of OH- ions is 0.01 M.
- Kw = 1 × 10^-14
- [OH-] = 0.01 M
- [H+] = Kw / [OH-] = 1 × 10^-14 / 0.01 = 1 × 10^-12 M
- pH = -log[H+] = -log(1 × 10^-12) = 12
- Example 2: Calculate the pH of a solution when the concentration of H+ ions is 1 × 10^-6 M.
- [H+] = 1 × 10^-6 M
- pH = -log[H+] = -log(1 × 10^-6) = 6
Conclusion
In this article, we addressed some of the frequently asked questions (FAQs) about H+ and OH- ions. We provided explanations and examples to help readers understand the relationship between H+ and OH- ions, the Kw value, and the pH scale. We hope that this article has been helpful in clarifying any doubts that readers may have had.