Question

2 P2S5(s) +16 H2O (l) -> 4 H3PO4 (aq) + 10 H2S (g) H2S production reaction

Fe2O3 + 3 H2S -> Fe2S3 +3 H2O   H2S neutralizing reaction

In the above production reaction, if the pH is 5 ( of the H3PO4 solution) how many moles of H2S would be present?

How many moles of Fe2O3 would thus be required to neutralize this many moles of H2S at ph 5?

Answer 1

Answer 2

IF H₂S is hydrolized:

$\frac{H^+_{H_3PO_4}}{H^+_{H_2S}}=\frac{12}{20}=\frac{3}{5}$

$H^+_{H_2S}=6.25*10^{-6}...........n_{H_2S}=3.125*10^{-6}$

IF H₂S is not hydrolized:

$[H^+]=10^{-5}.............n_{H^+}=10^{-5}$

$n_{H_3PO_4}=3.3*10^{-6}$

$4H_3PO_4................10H_2S$

$1Fe_2O_3........3H_2S$