112. CuS + NO > Cu2 + S04-2 + NO રેડોક્ષ-પ્રક્રિયા
ઍસિડિક માધ્યમમાં નીચેના પૈકી કઈ સમતુલિત પ્રક્રિયા છે ?
(a) 3CuS + 8NO9 + 8H
-> 3Cu2+ + 3S042- + 8NO + 4H2O
(b) CuS + 4NO + 4H+
→ 2Cu2+ + 3S042- + 4NO + 4H2O
(c) 3Cu + 8NO9 + 6H+
– 3Cu2+ + 3S042- + 8NO + 4H2O
(d) 3Cu + 8NO9 + 4H2O
- 3Cu2+ + 3S042- + 8NO + 8H+
Answers
Answer:
The elementary steps during oxidative chemisorption of SO2 by a novel composite material consisting of highly disordered benzene tri-carboxylate metal organic framework materials with Cu as central cation and BaCl2 as a second component (Ba/Cu-BTC) and by a conventional BaCO3/Al2O3/Pt based material were investigated. EXAFS analysis on the Cu K-edge in Ba/Cu-BTC indicates the opening of the majority of the Cu-Cu pairs present in the parent Cu-BTC. Compared to Cu-BTC, the BaCl2 loaded material has hardly any micropores and has higher disorder, but it has better accessibility of the Cu2+ cations. This results from the partial destruction of the MOF structure by reaction between BaCl2 and the Cu cations. The SO2 uptake in oxidative atmosphere was higher for the Ba/Cu-BTC sample than for the BaCO3/Al2O3/Pt based material. XRD showed that on Ba/Cu-BTC the formation of BaSO4 and CuSO4 occurs in parallel to the destruction of the crystalline structure. With BaCO3/Al2O3/Pt the disappearance of carbonates was accompanied with the formation of Ba- and Al-sulfates. XANES at the S K-edge was used to determine the oxidation states of sulfur and to differentiate between the sulfate species formed. At low temperatures (473 K) BaSO4 was formed preferentially (53 mol% BaSO4, 47 mol% CuSO4), while at higher temperatures (and higher sulfate loading) CuSO4 was the most abundant species (42 mol% BaSO4, 58 mol% CuSO4). In contrast, on the BaCO3/Al2O3/Pt based material the relative concentration of the sulfate species (i.e., BaSO4 and Al2(SO4)3) as function of the temperature remained constant.