Tuesday, July 1, 2008

Chemical Bonding - 12 - True or False type Questions

State whether the following statements are True or False.

1. Linear overlap of two atomic p-orbitals leads to a sigma bond. (JEE 1983)

True

2. The H-N-H bond angle in NH3 is greater than the H-As-H bond angle in AsH3. (JEE 1984)

True. Repulsion among bonds is more in NH3 and it makes bond angle greater.

3. All molecules with polar bonds have dipole moment. (JEE 1985)

False. Symmetrical molecules will have zero dipole moment.

4. SnCl2 is nonlinear molecule (JEE 1985)

True

5. sp2 hybrid orbitals have equal s- and p- character (JEE 1987)

False. One third s and two thirds p.


The presence of polar bonds in a polyatomic molecules suggests that molecule has non-zero dipole moment (JEE 1990)

False. Some polyatomic molecules having polar bonds have zero dipole moment.


H2O molecule is linear. (JEE 1993)

False. It is V-shaped.

The dipole moment of CH3F is greater than that of CH3Cl. (JEE 1993)

False. Dipole moment in CH3F is less than CH3Cl as bond length is shorter in CH3F. Remember the definition of dipole moment from physics.

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