In the process of desulfurization of flue gas, SO2 is passed through an absorber containing slaked lime in the presence of O2. The final product is
CaSO3.3H2O
Desulfurization Process Explained
Flue gas desulfurization (FGD) is a process used to remove sulfur dioxide (SO2) from the exhaust flue gases of fossil-fuel power plants, and from other sulfur oxide emitting processes.
Reaction with Slaked Lime
One common method for flue gas desulfurization is wet scrubbing using a sorbent like slaked lime. Slaked lime is calcium hydroxide, chemically represented as Ca(OH)2.
When SO2 gas from the flue gas passes through an absorber containing a slurry of slaked lime, it reacts with the slaked lime. The primary reaction producing calcium sulfite is:
$\text{SO}_2\text{(g)} + \text{Ca(OH)}_2\text{(aq)} \rightarrow \text{CaSO}_3\text{(s)} + \text{H}_2\text{O(l)}$
This reaction produces calcium sulfite (CaSO3) as a solid precipitate and water.
Presence of O2 and Final Product
The question mentions the presence of O2 in the process. While the presence of oxygen can lead to the oxidation of calcium sulfite (CaSO3) to calcium sulfate (CaSO4), especially in some FGD processes designed to produce gypsum (CaSO4 ⋅ 2H2O), the direct reaction between SO2 and slaked lime primarily yields calcium sulfite.
Calcium sulfite is sparingly soluble in water and tends to crystallize out as hydrates. The degree of hydration can vary depending on the process conditions like temperature and water content. Hydration means that water molecules are incorporated into the crystal structure of the solid.
Based on the options provided, the final product is given as a hydrated form of calcium sulfite.
The formation of calcium sulfite trihydrate involves the calcium sulfite crystal incorporating three water molecules:
$\text{CaSO}_3\text{(s)} + 3\text{H}_2\text{O(l)} \rightarrow \text{CaSO}_3 \sdot 3\text{H}_2\text{O(s)}$
Thus, in the process of desulfurization of flue gas where SO2 reacts with slaked lime, calcium sulfite is formed, which then hydrates to form calcium sulfite trihydrate (CaSO3 ⋅ 3H2O) under specific conditions.
Important Questions from p - Block
Which of the following has the lowest boiling point?
Which of the following reaction(s) do(es) NOT occur
(i) [NPCl2]3 + 6 NaF \(\rm \xrightarrow[reflux]{MeCN}\) [NPF2]3 + 6 NaCl
(ii) n PCl5 + n NH4Cl \(\rm \xrightarrow[reflux]{C_6H_5Cl}\) [NPCl2]n + 4 n HCl [n = 3, 4, 5]
(iii) n PF 5 + n NH 4 F \(\rm \xrightarrow[reflux]{C_6H_5Cl}\) [NPF 2 ] n + 4 n HF [n = 3, 4, 5]
Choose the correct statement(s) from the following:
(i) The trend in Lewis acidity among silicon halides is SiI4 < SiBr4 < SiCl4 < SiF4.
(ii) Tin(II) chloride can act as a Lewis acid and not as a Lewis base.
(iii) Aluminosilicates can display Brønsted acidity.
Consider following statements
A. PbCl2 has low solubility in water.
B. Sulfides of As(III) and Sb(III) are soluble in ammonium sulfide.
C. SnS is soluble in yellow ammonium sulfide.
D. MnS is precipitated by passing H2S through acidic MnCl2.
Correct statements are
Which of the statements (A‐D) given below are correct for B2H6 molecule:
A. Addition of Et2O•BF3 to NaBH4 in a polyether solvent produces B2H6.
B. It has D2d symmetry.
C. Reaction of B2H6 with NMe3 gives Me3N•BH3.
D. It is diamagnetic.
