How to Calculate the pH of 0.001 M NaCl?

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Discussion Overview

The discussion revolves around calculating the pH of a 0.001 M NaCl solution, exploring the implications of strong electrolytes on pH and the role of ionic strength in this context.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant inquires about the calculation of pH for 0.001 M NaCl and suggests a reaction involving NaCl, H2O, HCl, and NaOH, expressing uncertainty about the next steps.
  • Another participant asserts that sodium chloride is a strong electrolyte that dissociates completely in solution, indicating that it should not affect the pH, which they claim should ideally be 7.
  • A similar claim is reiterated that a NaCl solution of any concentration should ideally have a pH of 7, mentioning ionic strength and activity coefficients.
  • One participant argues that while ionic strength is relevant in buffer preparation, it may not significantly affect pH in this specific case.
  • Another participant counters that ionic strength is always an important factor in solutions containing ions, suggesting that the addition of neutral salt can influence pH, even if it does not change the numerical value in this instance.

Areas of Agreement / Disagreement

Participants express differing views on the impact of ionic strength on pH in NaCl solutions, indicating that there is no consensus on this aspect of the discussion.

Contextual Notes

Some assumptions regarding the behavior of strong electrolytes and the role of ionic strength in pH calculations remain unresolved, and the discussion does not clarify the specific conditions under which these claims hold true.

AdnamaLeigh
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How do you calculate the pH of 0.001 M NaCl? I was thinking of doing NaCl + H2O ---> HCl + NaOH but I don't know where to go from there if that's even the right step.
 
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Sodium Chloride is a strong electrolyte meaning it will disassociate completely in solution.
Strong electrolytes will not affect the pH of the solution as the acids / bases they form are also strong electrolytes.

A NaCl solution of any concentration should have (ideally) a pH of 7.


NaCl (aq) + H2O (l) ---> HCl (aq) + NaOH (aq)
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
 
Last edited:
The topic of ionic strength is practical with buffer preparation, however, I don't believe that it's an important factor with regard to the pH in this situation.
 
GCT said:
The topic of ionic strength is practical with buffer preparation, however, I don't believe that it's an important factor with regard to the pH in this situation.

It is an important factor in every solution containing ions. Even if it doesn't change numerical value of pH in this case, you can't assume that addition of neutral salt never changes pH of the solution.
 

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