Calculate The Ph of A 0.002 N Base Completely Dissociated
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Calculating the pH of a completely dissociated base solution is essential in chemistry and biology. This guide explains the process step-by-step, provides a calculator for quick results, and offers practical insights into interpreting the pH value.
Introduction
When a base is completely dissociated in water, it forms hydroxide ions (OH-) directly. The pH of such a solution can be calculated using the concentration of the hydroxide ions. This calculation is fundamental in understanding buffer systems, titration curves, and various chemical equilibria.
Key Concept: A completely dissociated base means all base molecules have dissociated into ions, simplifying the pH calculation.
How to Calculate the pH of a Completely Dissociated Base
The pH of a completely dissociated base solution is calculated using the following steps:
- Determine the concentration of hydroxide ions (OH-) formed by the base.
- Calculate the pOH using the hydroxide ion concentration.
- Convert pOH to pH using the relationship between pH and pOH.
Formula
The pH of a completely dissociated base solution is calculated using:
pH = 14 - pOH
Where pOH is calculated as:
pOH = -log[OH-]
For a base with concentration C (in moles per liter), the hydroxide ion concentration is equal to C because the base is completely dissociated.
Example Calculation
Let's calculate the pH of a 0.002 N (0.002 moles per liter) completely dissociated base solution.
- First, determine the hydroxide ion concentration: [OH-] = 0.002 M.
- Calculate pOH: pOH = -log(0.002) ≈ 2.699.
- Convert pOH to pH: pH = 14 - 2.699 ≈ 11.301.
Result: The pH of a 0.002 N completely dissociated base solution is approximately 11.30.
This result indicates a strongly basic solution, which aligns with the high concentration of hydroxide ions.
Practical Applications
Understanding the pH of completely dissociated base solutions is crucial in several practical scenarios:
- Buffer Solutions: Knowing the pH helps in designing buffer systems that maintain a stable pH.
- Titration Analysis: It aids in interpreting titration curves where bases are involved.
- Environmental Chemistry: Assessing the impact of industrial discharges on water bodies.
- Biological Systems: Understanding the pH of bodily fluids and their buffers.
| Base Concentration (N) | pH | Solution Type |
|---|---|---|
| 0.001 N | 12.30 | Strongly Basic |
| 0.002 N | 11.30 | Strongly Basic |
| 0.01 N | 10.30 | Moderately Basic |
| 0.1 N | 9.30 | Weakly Basic |
FAQ
What does "completely dissociated" mean?
A completely dissociated base means all base molecules have broken apart into ions in the solution. For example, NaOH completely dissociates into Na+ and OH- ions.
How does the concentration of the base affect the pH?
A higher concentration of the base leads to a higher concentration of hydroxide ions, resulting in a lower pH (more basic solution).
Can this calculation be used for partially dissociated bases?
No, this calculation is specifically for completely dissociated bases. For partially dissociated bases, you would need to consider the dissociation constant (Kb) of the base.
What is the significance of a pH of 11.30?
A pH of 11.30 indicates a strongly basic solution, which is highly alkaline. Such solutions can be corrosive and may react violently with acids.