A. SO2
B. H2S
C. CO2
D. C2H4
¨ Hydrogen sulfide (H2S) is the gas that cannot be dried by concentrated sulfuric acid (H2SO4). This is because H2S reacts with H2SO4 to form sulfur dioxide (SO2) and water (H2O) as follows:
¨ H2S + H2SO4 → SO2 + 2H2O
¨ The reaction with H2SO4 removes water from the system, but it also produces more water as a byproduct, which limits the effectiveness of H2SO4 as a drying agent for H2S. Therefore, other methods such as using a drying tube filled with a suitable drying agent like calcium chloride or magnesium perchlorate are preferred for drying H2S gas.
¨ SO2, CO2, and C2H4 can all be dried by concentrated sulfuric acid. SO2 and CO2 are acidic gases that readily dissolve in water to form sulfurous acid (H2SO3) and carbonic acid (H2CO3), respectively, but they do not react with H2SO4 in the same way as H2S. C2H4 is a non-polar gas and can be dried using H2SO4 or other suitable drying agents.
Submitted by :- Jamil Ahmed