Balance the equation for the disproportionation of sulfur into sulfide and thiosulfate (symbol in attachment) in base. Determine if the reaction spontaneous.
Second question also present in the attachment.© BrainMass Inc. brainmass.com December 24, 2021, 8:45 pm ad1c9bdddf
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In basic medium, the disproportionation of elemental sulfur into sulfide can be given as below:
4S + 4H2O SO42- + 3HS- + 5H+
This reaction occurs in basic medium.
whereas sulfide gives thiosulfate as shown below:
SO42- + HS- + H+ S2O32- + H2O
This reaction is more favorable in the acidic medium rather than basic medium.
Further, on the basis of entropy, we can explain the spontaneity of the reaction, the first reaction gives a positive entropy which means reaction can occur spontaneously whereas in the second reaction, the number of chemical species on right hand side are less than left hand side indicating negative entropy of the system and hence reaction is not spontaneous.
The given latimer diagram can be given as:
O2 -H2O2 -- H2O
0 -1 -2
the half cell reactions for H2O2 ( H2O and O2 ( H2O2 can be written as:
Reduction half cell reaction:
H2O2(aq) + 2H+(aq) + 2e- 2H2O(l) Eo = +1.77V
Oxidation half cell reaction:
O2(g) + 2H+(aq) + 2e- H2O2(aq) Eo = +0.68V
The difference between two half cell reactions will give cell potential for H2O2,O2||H2O2,H2O
2H2O2(aq) 2H2O(l) + O2(g) Ecell = 1.77-0.68 = +1.09V