Cal11 calculator
Search calculator...

Calculate The Ph of A 0.002 N Base Completely Dissociated

Reviewed by Calculator Editorial Team

This guide explains how to calculate the pH of a 0.002 N base that is completely dissociated in water. We'll cover the formula, step-by-step calculation, and interpretation of results.

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 base and the dissociation constant of water.

The pH of a completely dissociated base solution is determined by the concentration of hydroxide ions produced. For a base with concentration C (in moles per liter), the concentration of hydroxide ions [OH⁻] is equal to C because each molecule of base dissociates completely to produce one hydroxide ion.

How to Calculate

The pH of a completely dissociated base solution can be calculated using the following steps:

  1. Determine the concentration of the base in moles per liter (M or N).
  2. Since the base is completely dissociated, the concentration of hydroxide ions [OH⁻] is equal to the concentration of the base.
  3. Calculate the pOH using the formula: pOH = -log[OH⁻].
  4. Calculate the pH using the relationship: pH = 14 - pOH.

Formula

For a completely dissociated base with concentration C (in M or N):

[OH⁻] = C

pOH = -log[OH⁻]

pH = 14 - pOH

Example Calculation

Let's calculate the pH of a 0.002 N base that is completely dissociated.

  1. Given: Concentration of base (C) = 0.002 M (or N).
  2. Since the base is completely dissociated: [OH⁻] = 0.002 M.
  3. Calculate pOH: pOH = -log[0.002] ≈ 2.699.
  4. Calculate pH: pH = 14 - 2.699 ≈ 11.301.

The pH of the solution is approximately 11.30.

Interpretation

A pH of 11.30 indicates a strongly basic solution. This is expected because the base is completely dissociated, producing a high concentration of hydroxide ions.

In practical terms, this solution would:

  • Feel slippery to the touch due to the high hydroxide ion concentration.
  • React strongly with acids, neutralizing them completely.
  • Have a strong alkaline taste.

Note: The pH calculation assumes the base is completely dissociated and that the solution is at 25°C. For different temperatures, the dissociation constant of water would need to be adjusted.

FAQ

What does "completely dissociated" mean?
A completely dissociated base means that every molecule of the base breaks apart into ions in solution, producing hydroxide ions directly without any remaining undissociated molecules.
How does the concentration of the base affect the pH?
A higher concentration of base produces more hydroxide ions, resulting in a higher pH. Conversely, a lower concentration produces fewer hydroxide ions, resulting in a lower pH.
Can this calculation be used for any base?
This calculation applies specifically to bases that are completely dissociated. For partially dissociated bases, a different approach using the base's dissociation constant would be needed.