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GATE 2021 CY – Question 38

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). · 2 marks · Multiple choice

The shapes of $ClF_3$, $XeOF_2$, $N_3^-$ and $XeO_3F_2$, respectively, are ______.

  1. T-shape, T-shape, linear and trigonal bipyramidal
  2. trigonal planar, T-shape, V-shape and square pyramidal
  3. T-shape, trigonal planar, linear and square pyramidal
  4. trigonal planar, trigonal planar, V-shape and trigonal bipyramidal

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Correct answer: (A) T-shape, T-shape, linear and trigonal bipyramidal

Explanation

ClF3 is AX3E2 with two equatorial lone pairs in a trigonal-bipyramidal electron arrangement, giving a T shape. XeOF2 also has three bonded atoms and two lone pairs, giving a T shape. Azide has a linear three-atom skeleton. XeO3F2 has five bonding domains and no lone pair, giving trigonal bipyramidal geometry. This sequence is **A**.