Given below are two statements: In the light of the above statements, choose the most appropriate answer from the options given below:
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
Answer
(3) Statement I is correct but Statement II is incorrect
Solution
Cl has 7 valence electrons; 3 are used in bonding with 3 F atoms.
3 bond pairs + 2 lone pairs = 5 electron pairs trigonal bipyramidal arrangement.
The two lone pairs can be placed in three ways: both equatorial (I), one axial + one equatorial (II), both axial (III). So Statement I is correct.
Repulsions at 90 (as per NCERT):
I: lp–lp = 0, lp–bp = 4, bp–bp = 2
II: lp–lp = 1, lp–bp = 3, bp–bp = 2
III: lp–lp = 0, lp–bp = 6, bp–bp = 0
lp–lp > lp–bp > bp–bp, structure II (one lp–lp repulsion at 90 ) is least stable and structure III has the maximum lp–bp repulsions.
Structure I (lone pairs in equatorial positions) is the most stable ClF3 is T-shaped.
Axial lone pairs do not give minimum lp–bp repulsion, so Statement II is incorrect.
Answer: (3)