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GATE 2025 CY – Question 22

Inorganic Chemistry · Main Group Elements: Shapes and structures of molecules using VSEPR postulates, Hydrides, halides, oxides, oxoacids, nitrides, sulfides - shapes and reactivity. Structure and bonding of boranes, carboranes, silicones, silicates, boron nitride, borazine and phosphazenes: electron counting in polyhedral boranes, isolobal analogy. Allotropes of carbon, phosphorus and sulfur. Industrial synthesis of compounds of main group elements such as NH3, H2SO4 and HNO3. Chemistry of noble gases and interhalogen compounds. Acid-base concepts and principles (Lewis, Brønsted, HSAB and acid-base catalysis). · 1 mark · Multiple select

Under the conditions mentioned for each reaction, the reaction(s) that would give borazine (B3N3H6) as the major product is/are

Four reactions proposed to form borazine.
  1. Option A in the figure
  2. Option B in the figure
  3. Option C in the figure
  4. Option D in the figure

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Show answer and explanation

Correct answer: (A) Option A in the figure; (B) Option B in the figure

Explanation

Heating ammonium chloride with lithium borohydride or heating diborane with ammonia gives borazine. The lower-temperature borohydride route gives ammonia borane; boron trichloride with ammonium chloride does not supply the B–H bonds.

Official GATE 2025 answer key: https://gate2026.iitg.ac.in/doc/download/2025_Key/CY_Keys.pdf