How to Determine Proton Concentration in a Mixed Solution?

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Discussion Overview

The discussion revolves around determining the proton concentration in a mixed solution involving sulfuric acid (H2SO4) and sodium hydroxide (NaOH). Participants explore the stoichiometry of the reactions, the effects of mixing these solutions, and the implications for calculating hydronium ion (H3O+) concentration. The conversation includes theoretical considerations, reaction equations, and equilibrium concepts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • Some participants question whether to use the total volume of the mixed solution or the initial volume of H2SO4 when calculating moles.
  • There is confusion regarding the stoichiometry of the reaction between NaOH and H2SO4, particularly about the amounts needed for complete reaction.
  • Participants discuss the implications of having excess H2SO4 or NaOH and how this affects the resulting concentrations of H3O+ and HSO4-.
  • Equilibrium calculations are suggested to determine the concentration of H3O+ after considering the dissociation of HSO4-.
  • Some participants express uncertainty about the derivation of equilibrium equations and the significance of formal versus molar concentrations.
  • There is a proposal to solve a quadratic equation to find the concentration of H3O+, but participants express confusion about the variables involved.
  • Discussions include the need to account for the dissociation of HSO4- and its impact on the overall proton concentration.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct approach to calculate the proton concentration. There are multiple competing views regarding the stoichiometry of the reactions, the interpretation of equilibrium constants, and the calculations involved.

Contextual Notes

Limitations include unresolved assumptions about the initial concentrations and volumes, as well as the dependence on the definitions of formal and molar concentrations. The discussion also reflects varying levels of understanding of acid-base equilibria and stoichiometry.

Who May Find This Useful

This discussion may be useful for students and individuals interested in chemistry, particularly those studying acid-base reactions, stoichiometry, and equilibrium concepts.

  • #31
mjc123 said:
x is the concentration of H3O+, which is equal to the concentration of SO42-. 0.5-x is the concentration of HSO4-. We ignore the concentration of water as it is effectively constant.
Your solution to the quadratic equation is incorrect.
(I did not solve it. I only wrote it.)
 
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  • #32
Lifeforbetter said:
I don't know where this come from.. 0.5 - x and x refers to what concentration..
But i calculate
x = 0.01 +- 0.05##\sqrt2##
Study basic algebra: Algebra 1 and Algebra 2;
then study Elementary Chemistry, and the first or the first AND second semesters of General Chemistry; only then may you understand these topics.
 

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