Within India’s fertilizer industry, which plant historically obtained hydrogen via electrolysis of water for ammonia synthesis feed preparation?

Introduction / Context:
Hydrogen for ammonia synthesis is usually produced by natural-gas steam reforming or naphtha reforming. However, certain plants have used water electrolysis, particularly where inexpensive hydroelectric power is available. Recognizing such exceptions is a classic exam topic in fertilizer technology.

Given Data / Assumptions:

• Electrolysis of water takes significant electrical energy.
• Locations with access to hydropower historically adopted this route.
• The question asks for the specific Indian plant known for this practice.

Concept / Approach:
Nangal (Punjab) is well known for integrating hydroelectric power from the Bhakra-Nangal project, enabling hydrogen generation by water electrolysis for its ammonia unit, especially in earlier configurations before widespread gas-based reforming dominance.

Step-by-Step Solution:
Identify which site aligns with hydroelectric infrastructure.Nangal corresponds to Bhakra-Nangal hydropower, making electrolysis economical at that time.Select Nangal as the plant obtaining H2 by electrolysis.

Verification / Alternative check:
Historical plant summaries and training manuals routinely cite Nangal as the example of electrolysis-based hydrogen in Indian ammonia production.

Why Other Options Are Wrong:
Namrup, Rourkela, Korba: these sites are associated with alternate feedstocks or steel/chemical complexes, not the classic electrolysis case.

Common Pitfalls:
Assuming all fertilizer hydrogen is from reforming; overlooking legacy processes adapted to local power sources.

Final Answer:
Nangal