How Does Electrolysis Affect pH in a HBr Solution?

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Discussion Overview

The discussion revolves around the effect of electrolysis on the pH of a hydrochloric acid (HBr) solution, specifically focusing on a homework problem involving the application of a current to the solution and the resulting changes in hydrogen ion concentration.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant presents a calculation involving the conversion of H+ ions to hydrogen gas (H2) during electrolysis, leading to a proposed pH value.
  • Another participant points out the need to consider the initial concentration of H+ ions and the effect of electrolysis on the remaining concentration.
  • A later reply indicates that the initial calculation was corrected or adjusted, suggesting a successful resolution of the problem.

Areas of Agreement / Disagreement

The discussion shows a progression from an initial calculation to a correction, indicating that there was uncertainty in the initial approach, but it appears that the final response was satisfactory for at least one participant.

Contextual Notes

The initial calculation may have lacked clarity on the assumptions regarding the starting concentration of H+ and the extent of its reduction due to electrolysis. The exact nature of the corrections made is not detailed.

harrietstowe
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Homework Statement


A current of 10.7 Amps is applied to a 1.30 L solution of 0.550M HBr converting some of the H+ to H2(g), which bubbles out of solution. What is the PH of the solution after 77 minutes.


Homework Equations





The Attempt at a Solution


(10.7 C/s)(1 mol e/96485 C)(2 mol H+/2 mol e)(60s/min)(77 min) = .512 mol H+

.512 mol H+/1.30L = .394M H+
-log(.394M) = .405 = PH

This was incorrect
 
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You started with a certain amount of H+ in the solution. The electrolysis removed some. Now you need to calculate what's left.
 
I see will try, thank you
 
It worked, thank you
 

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