Question

Which of the following is formed when SO3 is absorbed by concentrated H2SO4?

• A. H2S2O8
• B. H2SO3
• C. H2S2O7
• D. H2S2O5

Hint:

SO3} reacts with H2}SO4} to form oleum, H2}S2}O7}, not peroxodisulfuric acid (H2}S2}O8}).

Answer 1

The Correct Option is C

SO3} + H2}SO4} → H2}S2}O7} (Oleum)
This is the industrial method of preparing oleum