Class 11 Chemistry Chemical Bonding mcqs ( Part 3)

Class 11 Chemistry Chemical Bonding mcqs

A molecule with the smallest angle b/w two adjacent bonds is:

1.CO2

2.CH4

3.NH3

4.H2O

Answer ) H2O

Brief Explanation :

H2O molecule with the smallest angle b/w two adjacent bonds due to the compression of two bond pairs by the two lone pairs of electrons on the oxygen atom.

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A molecular orbital with higher energy than the atomic orbitals is:

1. BMO

2. ABMO

3. Hybrid orbitals

4. Un-Hybrid orbitals

Answer ) ABMO

Brief Explanation :

  An anti-bonding MO  has always higher energy than the atomic orbitals.

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Hybridization of carbon in  CH3-O-CH3 is :

1.sp³

2.sp²

3.sp

4.dsp²

Answer ) sp³

Brief Explanation :

Carbon in CH3-O-CH3 (Dimethyl ether ) is sp³ hybridized and has a bent shape.

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Carboxylic acid in acetic acid [ CH3COOH ] is hybridized:

1.sp

2.sp²

3.sp³

4.dsp²

Answer ) sp²

Brief Explanation :

Carboxylic acid in acetic acid [ CH3-CO-OH ] is attached to three other atoms and thus sp² hybridized.

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Dipole moment can not be used to predict / identify :

1.% ionic character

2. Geometry of molecules

3. Cis – trans isomers

4. Limiting reactant

Answer ) Limiting reactant

Brief Explanation :

Dipole moment can be used to predict % ionic character, the geometry of molecules and also identify cis – trans isomers.

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Bond order gives information about:

1. Bond energy

2. Bond length

3. Stability of molecule/ion

4. All of these

Answer )   All of these

Brief Explanation :

Bond order is half of the difference between the number of electrons in the bonding and antibonding molecular orbitals.

It gives information about bond energy, bond length and stability of molecule/ion.

The higher the bond order, the greater the stability and bond energy while the shorter is the bond length.

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A tetra atomic molecule with zero dipole moment is:

1. Bent

2. Pyramidal

3. Unsymmetrical

4. Planar Trigonal

Answer ) Planar Trigonal

Brief Explanation :

 Tetra atomic molecules like BF₃, BH₃ etc with zero dipole moment have planar Trigonal shapes.

The different bond moments cancel out each other effect and the resultant dipole moment is zero.

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Oxygen is paramagnetic due to the presence of:

1. Unpaired electrons in AOs

2. Unpaired electrons in BMOs

3. Unpaired electrons in ABMOs

4. Paired electrons in ABMOs

Answer )Unpaired electrons in ABMOs

Brief Explanation :

Oxygen is paramagnetic due to the presence of two unpaired Electrons in ABMOs.

An unpaired electron produces a magnetic field due to spinning around its own axis & act as a small magnet.

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Bond energy does not depend upon:

1. Polarity of bond

2. Multiplicity of bond

3. Size of bonded atoms

4. None of these

Answer ) None of these

Brief Explanation :

Bond energy increases with the increase in polarity & multiplicity of bond while decreases with the increase in the size of bonded atoms.

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The bond dissociation energy of a covalent bond decreases with an increase in:

1. Polarity

2. Multiplicity of bond

3. Size of atoms

4. None of these

Answer ) Size of bonded atoms

Brief Explanation :

The bond dissociation energy of a covalent bond decreases with an increase in the size of bonded atoms.

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When the s-character of a hybrid orbital increase, bond length :

1. Remains constant

2. Increases

3. Decreases

4. Not well defined

Answer ) Decreases

Brief Explanation :

When the s-character of the hybrid orbital increases, bond length decreases.

For example , C-C bond length in ethane (sp³) , ethylene (sp²) and acetylene ( sp) are 1.54 A^o  , 1.34 A^o  & 1.20 A^o  .

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Dipole moment is generally expressed in units of Debye (D):

1.1 D = 1.6 X 10 ²³ C.m

2.1 D = 3.34 X 10 ^-19 C.m

3.1 D = 3.34 X 10 ^-30 C.m

4.1 D = 6.62 X 10 ^-34 C.m

Answer ) 1 D = 3.34 X 10 ^-30 C.m

Brief Explanation :

Dipole moment is generally expressed in units of Debye (D) in the C.G.S system.Its S.I unit is coulombs x meter (c.m)

Where :

1 D = 3.34 X 10 ^-30 C.m

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