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1 Molecular Orbital Theory. Which of the following has zero bond order? N ) O F. The bond order of superoxide ion [ O ] is ) Bonding electrons present in N molecule are ) Bond order of H is similar to N ) O Li F 5. Which of the following is paramagnetic with bond order? O ) O N O+ 6. Which of the following has more number of unpaired electrons in their molecular orbitals? C ) N O F 7. For a homodiatomic molecule with a total number of 6 electrons, after filling *s, the next electron enters in to px ) py or px py He Pz 8. Which of the following pair of molecular orbitals ore degenerate? * s, s ) s, *s py, * py px py,

2 9. H and H ions have the same bond order of 0.5, but H is slightly less stable than H.This is due to It is anion. ) One electron in the bonding orbital. One electron in the anti bonding orbital. Two electrons in bonding orbital. 0. Addition of wave functions of ya and yb of atomic orbitals A and B form Bonding molecular orbitals ) Anti-bonding molecular orbitals Both bonding and antibonding molecular orbitals Hybrid orbitals. The filling up of molecular orbitals with electrons follows a) Aufbau principle b) Hund s rule c) Pauli s principle a only ) a and c only b and c only a, b and c O,O,O. The bond length in and O follows the order O O O O ) O O O O O O O O O O O O 3. Which of the following is incorrect regarding molecular orbitals? Bonding molecular orbital has less energy than the combining atomic orbital. ) Bonding molecular orbital has no nodal plane. Anti-bonding molecular orbitals has nodal plane. Anti-bonding molecular orbital stabilizes the molecules.

3 4. Which of the following has a bond order of 0.5? H ) H N Ne 5. When N changes to N+, then N-N bond distance and O changes to O+, then O-O bond distance Increases, decreases ) Decreases, increases Increases in both cases Decreases in both cases 6. The highest bond strength is for O- ) B N+ He 7. Bond order of Be is 0 ) 3 8. Which one of the following correctly represents, the increasing order of their stability ) 9. Which of the following statement is correct? The peroxide ion has bond order of ½ while the oxygen molecule has bond order of zero ) The peroxide ion has a longer and weaker bond than the oxygen molecule The peroxide ion as well as the oxygen molecule are paramagnetic The bond length of the peroxide ion is smaller than that of O molecule 0. Bond order in peroxide ion is Larger than in O molecule ) Smaller than in superoxide ion Equal to that in N molecule Greater than in F molecule

4 . Bond order and magnetic behaviour of O is, diamagnetic ), diamagnetic, paramagnetic, paramagnetic. The number of antibonding electron pairs in molecular orbital theory is O ion on the basis of ) According, to MOT, the number of unpaired electrons in O molecule is ) 4 Zero 4. According, to MOT, the bond order of a molecule is equal to Total no. of bonding electrons ) Total no. of anti-bonding electrons Half the difference between no.of bonding electrons and antibonding electrons The difference between no.of bonding and antibonding electrons. 5. Molecule/ion Bond order A) O.5 B) O ).0 C) O- D) O.5 A B C D A B C D 3 4 )

5 6. The bond order in O is same as in N+ ) CN NO+ CO 7. Which of the following species is paramagnetic? O- ) CN CO 8. Which of the following is not paramagnetic? N+ ) CO O O NO 9. Which of the following species has the lowest bond order? O ) O O- 30. Which set of the following species has a bond order of.5? N,NO,O ) O, NO,CN N,CN,O 3. Which of the following set are isoelectronic? N,O ) O CN, N,O N,O N+, O+ N,O 3. Which of the following diatomic species do you expect to have the longest bond length? N ) 33. According, to MOT O O O- N+ has Three unpaired electrons ) Bond order of.5 Stability less than NO Diamagnetic character

6 34. Which one of the following statement regarding molecular orbital is incorrect? The energy of the anti bonding M.O is more than the combining atomic orbital and it destabilizes the molecule. ) The energy of the bonding M.O is less than the combining atomic orbital and it stabilizes the molecule. The increase in the energy of anti bonding molecular orbital is same as the decrease in the energy of bonding molecular orbital The no. of bonding M.O s is twice to Anti bonding M.O s 35. For a homodiatomic molecule with a total number of electrons 4 after filling * s M.O the next electron goes to pz ) px py 36. Which of the following ion has not bond order of.5? O- ) O N+ N- or px py The common features among the species CN, CO and NO are : Bond order 3 and isoelectronics ) Bond order and isoelectronics Bond order, 5 and isoelectronics Bond order.5 and isoelectronics 38. Which of the following species has the shortest bond length? N+ ) N N- 39. Among the following which one is paramagnetic? He ) O- Li Ne 40. Which of the following should be most stable? He ) H He H+ N -

7 KEY 4 ) 3 4 5) 6) 3 7) 4 8)4 9) 3 0) 4 4 5) 6)3 7) 8) 9) 0) 3 ) 3 5) 6) 7) 8) 9)4 30) )4 36) 37) 38) 39) 40)