Quantitative Titration of Unknown Solid Acid: Find Molar Mass & Formula

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Discussion Overview

The discussion revolves around the quantitative titration of an unknown solid acid to determine its molar mass and formula. Participants explore the relationship between the mass of the acid, the volume of titrant used, and the stoichiometry of the reaction with NaOH, focusing on the implications of the acid being monoprotic.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant proposes that it is possible to find the molar mass of the acid using the mass of the sample and the volume of NaOH used in the titration.
  • Another participant suggests calculating the acid dissociation constant (Ka) to find the number of H+ ions in the solution, indicating a different approach to the problem.
  • A third participant counters that the acid dissociation constant is unrelated to the problem and emphasizes that the stoichiometry of the neutralization reaction is sufficient to calculate the number of moles and thus the molar mass.
  • A later reply acknowledges a misunderstanding regarding the relevance of Ka, indicating that different methods were learned in exams.

Areas of Agreement / Disagreement

There is disagreement regarding the necessity of the acid dissociation constant in solving the problem. Some participants advocate for its relevance, while others assert that it is unnecessary and that stoichiometry alone suffices.

Contextual Notes

Participants express varying levels of familiarity with the concepts involved, leading to different proposed methods for solving the problem. The discussion reflects uncertainty about the applicability of certain formulas in this context.

Who May Find This Useful

This discussion may be useful for students or individuals interested in analytical chemistry, particularly those learning about titration techniques and the determination of molar mass through stoichiometric calculations.

jessica.so
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If you were given a sample unknown solid acid that had a mass of 0.7 g and it was being dissolved in 50 mL of water and was being titrated with NaOH, is it possible to find the molar mass or the formula of the acid?

Given information
Mass of solid acid: 0.7 g
Volume of acid solution: 50 mL = 0.05 L
Volume of base used: 29.5 mL = 0.0295 L
[NaOH] = 0.095 mol/L

I was also told that this is monoprotic.
HX (aq) + NaOH (aq) --> H2O (l) + NaX (aq)
 
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Hi,
I would try to get the Acid dissociation constant with this little formula:
Ka=( [A-]*[H+])/[HA]
How many H+ were in the solution?
How many mol are 0,7 g H+ ?= c (O)
HA = c0 H+ - [H+].
Then you just have to search for the specific the ka in and you have you acid.
Greetings Firelion
 
No need for acid dissociation constant, in fact it is completely unrelated to problem.

If acid is monoprotic you can easily calculate number of moles from the neutralization stoichiometry. Then you know mass of the sample and number of moles in the sample - that's enough to calculate molar mass.

--
 
oh sorry.
We leraned in our exams to calculate very different types of data with the Ka so I thought this task is similar.
 

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