जड पाण्याच्या बाबतीत खालीलपैकी कोणते एक विधान सत्य नाही ?
(1) जड पाणी हे ड्युटेरीयम ऑक्साईड आहे.
(2) ते उच्च दाबाच्या जड पाणी अणुभट्टीत, नियंत्रक (मॉडरेटर) व शीतलक (कुलंट) म्हणून वापरले जाते.
(3) भारत, जड पाण्याचा, जगात सर्वात मोठा उत्पादक आहे.
(4) भाभा अणुसंशोधन केंद्र (BARC) चा जड पाणी निर्मितीत सहभाग आहे.

This question was cancelled (#) in the official MPSC final answer key.

Key Points:
• Cancelled Question: In the official final revised answer key published by the MPSC, this question was marked with a `#` symbol (Cancelled) for Set A, Q.87.
• Heavy Water Science & Industry:
• Heavy water is chemically Deuterium Oxide (D₂O).
• Used as both moderator (slowing fast neutrons) and coolant in Pressurized Heavy Water Reactors (PHWRs).
• The Heavy Water Board (HWB), an industrial unit under the Department of Atomic Energy (DAE), operates plants across India (Manuguru, Kota, Thal, Hazira, etc.).
• Reason for Cancellation: Both statement (3) (China/India claims on largest production capacity) and statement (4) (HWB produces industrial heavy water, while BARC conducts R&D) created factual ambiguity as to which statement was the single intended false answer, leading the Commission to cancel the question.
• Key Takeaway: Question cancelled (#) by MPSC due to ambiguities regarding global production ranks and institutional production roles.