...convert ferrous sulphate into ferric sulphate...

Answer by Cool
Submitted on 7/12/2005
Rating: Not yet rated	Rate this answer:
MECHANISMS OF THE OXIDATION OF Fe(II) If the thermodynamics of the oxidation of Fe(II) are so favourable, why is the reaction so relatively slow? As noted above, due to its position in the electrochemical series, molecular oxygen is a powerful oxidising agent [ ]. However, reactions involving molecular oxygen in solution at room temperature usually proceed relatively slowly, due in large measure to the stepwise reduction of molecular oxygen to form water. Except under unusual conditions [18], the reduction of molecular oxygen to form water as per reaction 3 must occur in either two two-electron steps: 2 e + 2 H+ + O2 = H2O2 Eo = 0.68 V [18] … reaction 7, H2O2 + 2 e + 2 H+ = 2 H2O Eo = 1.776 V [7] … reaction 8, or four one-electron steps: e + H+ + O2 = HO2· Eo = -0.32 V [18] … reaction 9, HO2· + e + H+ = H2O2 Eo = 1.68 V [18] … reaction 10, H2O2 + e = OH· + OH- Eo = 0.80 V [18] … reaction 11, and e + H+ + OH· = H2O Eo = 2.74 V [18] … reaction 12. In the above, HO2· and OH· are radical species, which are atoms or groups of atoms that contain one or more unpaired electrons, and are quite unstable and reactive. The reactivity of the O2 molecule is thus determined by reaction 7, which is thermodynamically unfavourable and needs to occur before the more favourable subsequent reactions [18]. By the same token, reactions involving the oxidation of metal species by dissolved oxygen will be relatively slow, in the minutes to hours range. While there are a number of reactions in the oxidation of Fe(II) [ ], Fallab [18] proposed that the actual reactive species is Fe(OH)+, which is present in low concentrations. The reaction kinetics correspond to a mechanism in which the reaction with the oxygen molecule itself is rate-determining: Fe(OH)+ + O2 + H+ = Fe(OH)2+ + HO2· … reaction 13, followed by: Fe2+ + HO2· + H2O = Fe(OH)2+ + H2O2 … reaction 14, Fe2+ + H2O2 = Fe(OH)2+ + OH· … reaction 15, and Fe2+ + OH· = Fe(OH)2+ … reaction 16. Reactions 14-16, which involve H2O2 and the radicals HO2· and OH·, would be relatively fast. With further hydrolysis and nucleation [19]: Fe(OH)2+ + OH- = Fe(OH)3(s) Eo = 2.06 V [7] … reaction 16, which is thermodynamically highly favourable.

FAQS.ORG makes no guarantees as to the accuracy of the posts. Each post is the personal opinion of the poster. These posts are not intended to substitute for medical, tax, legal, investment, accounting, or other professional advice. FAQS.ORG does not endorse any opinion or any product or service mentioned mentioned in these posts.

<< Back to: Sci.chem FAQ - Part 1 of 7

[ Home | FAQ-Related Q&As | General Q&As | Answered Questions ]

Question by mathalai rajan
Submitted on 4/28/2004
Related FAQ: Sci.chem FAQ - Part 1 of 7
Rating:	Rate this question:
how to convert ferrous sulphate into ferric sulphate ecnomically

Answer by farhat jamal
Submitted on 8/8/2004
Rating: Not yet rated	Rate this answer:
please give the conversion process

Answer by as'hab
Submitted on 11/7/2004
Rating: Not yet rated	Rate this answer:
how to convert ferrous sulphate into ferric sulphate ecnomically

Answer by sushanta
Submitted on 12/20/2005
Rating: Not yet rated	Rate this answer:
ferrous sulphate can be converted to ferric sulphate by adding hydrogen peroxide

Answer by JbphyOzziQ
Submitted on 2/18/2006
Rating: Not yet rated	Rate this answer:
o22DiBzJrWwWoX J6leFQQpm2KmZJ LkqHPaFuxu

Answer by G.Dixon
Submitted on 3/12/2006
Rating: Not yet rated	Rate this answer:
Oxidation using air in alkaline conditions

Answer by JZ
Submitted on 11/11/2006
Rating: Not yet rated	Rate this answer:
add H2O2

Answer by neevine
Submitted on 1/23/2007
Rating: Not yet rated	Rate this answer:
oxidation

Your name or nickname:
If you'd like to create a new account or access your existing account, put in your password here:
Your answer: