Sulfuric acid manufacture: Regarding the historical lead chamber process, which statement is correct about its capability and mode of operation compared with the contact process?

Introduction / Context:
Two major processes have produced sulfuric acid industrially: the older lead chamber process and the modern contact process. Distinguishing their product strengths and operating principles is a common exam topic.

Given Data / Assumptions:

• Lead chamber process (LCP) employs nitrogen oxides (NOx) as homogeneous catalysts.
• Contact process uses solid vanadium pentoxide catalysts on porous supports.
• Product strengths differ substantially.

Concept / Approach:
LCP typically yields sulfuric acid around 62–70% by mass; stronger acid cannot be produced directly due to limitations of the chamber system. Oleums and 98% acid are the domain of the contact process. LCP is catalytic (NO/NO2 cycle) and can use sulfur or pyrites as SO2 sources. It is not a batch process; it historically operated continuously.

Step-by-Step Solution:
Check product strength claim → 98–100% is not produced by LCP.Check catalysis claim → LCP is catalytic with NOx, so “non-catalytic” is false.Check batch claim → LCP historically continuous; not a batch route to strong acid.Hence none of the statements (a–c) is correct → choose “None of these”.

Verification / Alternative check:
Classical chemical technology texts document LCP acid strengths and NOx catalysis details; oleum requires contact process absorption in 100% H2SO4.

Why Other Options Are Wrong:

• (a) Oleum/98% belong to contact process, not LCP.
• (b) LCP is catalytic and not restricted to pyrites alone.
• (c) Not batch; and it cannot directly give 98–100% acid.

Common Pitfalls:
Assuming “older” means “non-catalytic” and confusing which process makes oleum.

Final Answer:
None of these