Answer to Question #176371 in Organic Chemistry for Ashley

Question

Hi! I have a problem solving this question, could someone help me?

In the deeper parts of peat, the pe-value is buffered by the sulfur system, meanwhile the iron and mangan system buffers in the more superficial and oxidating peat layers

 

a) Calculate pe and the oxygen pressure (P_O2) in depth when the pH-value is 6.5 an if pe buffers by the following redox pair: SO₄^2- / HS^-(aq) where [SO₄^2-] = 0.0002 M and P_H2S(g) = 10^-4 atm

 

b) At another spot with pH = 6.0 the oxygen pressure was 10^-15 atm. Calculate the Mn²⁺ content if the redox pair MnO₂(s) / MN²⁺ buffers pe. 

Answer 1

$H_2S + 2O_2 \to H_2SO_4$

$6.5 =\dfrac{(0.0002)}{(10^{-4})×2x²}$

2x² = $\dfrac{(0.0002)}{(10^{-4}) × 6.5}$

2x² = 0.31

x = 0.4M