JEE Main · 2023 · Shift-ImediumPB11-018

Given below are two statements: Statement I: Boron is extremely hard indicating its high lattice energy. Statement II:…

p-Block Elements (Class 11) · Class 11 · JEE Main Previous Year Question

Question

Given below are two statements:

Statement I: Boron is extremely hard indicating its high lattice energy. Statement II: Boron has highest melting and boiling point compared to its other group members.

In the light of the above statements, choose the most appropriate answer from the options given below:

Options
  1. a

    Both Statement I and Statement II are incorrect

  2. b

    Statement I is correct but Statement II is incorrect

  3. c

    Both Statement I and Statement II are correct

  4. d

    Statement I is incorrect but Statement II is correct

Correct Answerc

Both Statement I and Statement II are correct

Detailed Solution

Strategy: Verify both statements about Boron's hardness (lattice energy) and its melting/boiling points in Group 13.

Step 1: Statement I — Hardness and Lattice Energy Boron is an extremely hard solid (hardness ~9.5 on Mohs scale) because it forms a covalent 3D network solid with icosahedral \ceB12\ce{B12} clusters linked by strong covalent bonds. High hardness implies high lattice energy. ✅ Statement I is correct.

Step 2: Statement II — Highest MP/BP in Group 13 | Element | MP (K) | |---------|--------| | B | 2453 | | Al | 933 | | Ga | 303 | | In | 430 | | Tl | 577 |

Boron has by far the highest melting and boiling point in Group 13. ✅ Statement II is correct.

Answer: (C) Both Statement I and Statement II are correct\boxed{\text{Answer: (C) Both Statement I and Statement II are correct}}

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Given below are two statements: Statement I: Boron is extremely hard indicating its high lattice… (JEE Main 2023) | Canvas Classes