Monday, October 29, 2007

IIT JEE Chemistry Questions Ch.5. BONDING AND MOLECULAR STRUCTURE

Orbital overlap and covalent bond;
Hybridisation involving s, p and d orbitals only;
Orbital energy diagrams for homonuclear diatomic species;
Hydrogen bond;
Polarity in molecules, dipole moment (qualitative aspects only);
VSEPR model and shapes of molecules (linear, angular, triangular, square planar, pyramidal, square pyramidal, trigonal bipyramidal, tetrahedral and octahedral).

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Theory Questions

Orbital overlap and covalent bond;
1. State the octet rule?
2. What are the instances where octet rule was found inadequate?
3. What is covalent bond?
4. What is coordinate covalent bond?
5. Name some molecules of having same atoms that have double bond.
6. Name some molecules of having same atoms that have triple double bond.
7. Name some compounds where N atom does not complete it octet.
8. do covalent bonds have directional character.
9. what is a coordinate bond?
10. give some examples of molecules having coordinate bonds.


Hybridisation involving s, p and d orbitals only;
1. Explain the need for the concept of hybridization?
2. Exlain the concept of hybridization.
3.

Orbital energy diagrams for homonuclear diatomic species;


VSEPR model and shapes of molecules (linear, angular, triangular, square planar, pyramidal, square pyramidal, trigonal bipyramidal, tetrahedral and octahedral).

1. What is VSEPR formulated? What does it try to explain?
2. What are the postulates of VSEPR theory?
3. What is the strength of repulsive forces over various possible pairs of electrons?
4.Why there are distortions in certain molecules from standard geometrical shapes indicated by the number of electron pairs?
5. Give examples of molecules that have linear arrangement of atoms.
6. Give examples of molecules that have trigonal planar arrangement of atoms.
7. Give examples of molecules that have tetrahedral arrangement of atoms.
8.Give examples of molecules that have trigonal bipyramidal arrangement of atoms.
9. Give examples of molecules that have octahedral arrangement of atoms.
10. Give examples of molecules that have pentagonal bipyramidal arrangement of atoms.
11. Give the geometrical shapes for molecules havng 2 to 7 electronic pairs around the central atom in a molecule.


Polarity in molecules, dipole moment (qualitative aspects only);


Hydrogen bond;


Concepts

1. State the octet rule?
2. What are the instances where octet rule was found inadequate?
3. Give important features of valence bond theory.
4. give different overlaps between 's' and 'p' orbitals and also give one example of each.
5. Explain the need for the concept of hybridization?
6. Exlain the concept of hybridization.
7. Explain the formation of sigma bond.
8.Explain the formation of pi bond.
9. Define bond energy?
10. What is ionic bond?
11. What is covalent bond?
12. What is coordinate covalent bond?


Applications and Examples

1. Why is H-F bond polar?
2. Give the geometry of hyubridised orbital in the following compounds.
a. Methane
b. water
c. ethyne
d. Boron trifluoride
e. Ammonia
f. BeF-2
g. ethene

3. Why bond angle in ammonia molecule is less than the expected tetrahedral bond angle?
4. There is only one pi-bond in ethylene molecule but here are two pi-bonds in the acytylene moecule. Explain.
5. Why a sigma bond is stronger than pi-bond?
6. The bond energy of PCl-3 is larger than the bond energy ni PCl-5. Why?
7. Bond energy in HF is larger than HI. Why?
8. Why H-O-H bond angle in water molecule is reduced to 104° 35'?

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