JEE Main · 2022 · Shift-IIeasyBOND-132

Arrange the following in increasing order of covalent character: (A) CaF2 (B) CaCl2 (C) CaBr2 (D) CaI2

Chemical Bonding · Class 11 · JEE Main Previous Year Question

Question

Arrange the following in increasing order of covalent character:

(A) CaF2\mathrm{CaF_2} (B) CaCl2\mathrm{CaCl_2} (C) CaBr2\mathrm{CaBr_2} (D) CaI2\mathrm{CaI_2}

Options
  1. a

    B < A < C < D

  2. b

    A < B < C < D

  3. c

    A < B < D < C

  4. d

    A < C < B < D

Correct Answerb

A < B < C < D

Detailed Solution

🧠 All four compounds share the same cation (Ca²⁺). Covalent character depends only on the polarisability of the anion.

🗺️ Polarisability order of halide ions:

F<Cl<Br<I\mathrm{F^- < Cl^- < Br^- < I^-}

Larger anion → more polarisable → more distorted by Ca²⁺ → more covalent character.

Increasing covalent character:

CaF2<CaCl2<CaBr2<CaI2\mathrm{CaF_2 < CaCl_2 < CaBr_2 < CaI_2}

⚡ This is the standard anion size/polarisability argument. The cation is held constant, so it's a clean test of one Fajans' rule variable.

Answer: CaF2<CaCl2<CaBr2<CaI2\boxed{\text{Answer: } \mathrm{CaF_2 < CaCl_2 < CaBr_2 < CaI_2}}

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Arrange the following in increasing order of covalent character: (A) CaF2 (B) CaCl2 (C) CaBr2 (D)… (JEE Main 2022) | Canvas Classes