imp questions from chemical bonding for jee.
Answers
Answer:
The bond dissociation energy of B–F in BF3 is 646 kJ mol-1 whereas that of C–F in CF4 is 515 kJ mol–1. ...
Solution: ...
Among the following species which two have trigonal bipyramidal shape ?
(1) NI3 (2) I3– (3) SO32- (4) NO3– ...
The bond dissociation energy of B–F in BF3 is 646 kJ mol-1 whereas that of C–F in CF4 is 515 kJ mol–1. The correct reason for higher B–F bond dissociation energy as compared to that of C–F is
(1) Significant pπ – pπ interaction between B and F in BF3 whereas there is no possibility of such interaction between C and F in CF4.
(2) Lower degree of pπ – pπ interaction between B and F in BF3 than that
between C and F in CF4
(3) Smaller size of B-atom as compared to that of C-atom
(4) Stronger bond between B and F in BF3 as compared to that between C and F in CF4.
Solution:
Because of pπ – pπ back bonding in BF3 molecule, all B-F bond having partial double bond character.
Hence option (1) is the answer.
2. Among the following species which two have trigonal bipyramidal shape ?
(1) NI3 (2) I3– (3) SO32- (4) NO3–
(1) II and III
(2) III and IV
(3) I and IV
(4) I and III
Solution:
Let us find the hybridization (H) and shape of given species.
(1) For NI3, H = ½ (5+3) = 8/2 = 4 → sp3 hybridized state. It is trigonal pyramidal in shape.
(2) For I3–, H = ½ (7+2+1) = 10/2 = 5 → sp3d hybridized state. It is linear in shape.
(3) For SO32-, H = ½ (6+2) = 8/2 = 4 → sp3 hybridized state. It is trigonal pyramidal in shape.
(4) For NO3–, H = ½ (5+1) = 6/2 = 3 → sp2 hybridized state. It is trigonal planar in shape.
Hence option (4) is the answer.
Answer:
The bond dissociation energy of B–F in BF3 is 646 kJ mol-1 whereas that of C–F in CF4 is 515 kJ mol–1. ...
Solution: ...
Among the following species which two have trigonal bipyramidal shape ?
(1) NI3 (2) I3– (3) SO32- (4) NO3– ...
Solution: