Electrophilic Aromatic Substitution Reactions MCQ

MCQ on Basics of Aromaticity

To be a Aromatic Compound molecule must

Molecule must fulfill following condition to be Aromatic.

• Compound must be cyclic
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• The molecule must be Planner. [ Possible when carbon in SP2 and SP ]
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• Every atom of cyclic chain must have an available p-orbital.
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• Should satisfy Huckel`s Rule [4n+2] pi electrons where, the number of electrons in the pi system must be 2, 6, 10, 14, 18, or a higher number i.e. integer value.
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Distinguishing the Aromatic and non Aromatic compounds?

Aromatic compounds

• Are Cyclic Structure
• Planar [ all atoms of cyclic ring in SP2 or SP Hybridization ]
• Satisfy Huckle`s rule [ 4n + 2  = pi ]
• Resonance stabilized
• Negative Bromine test [ Test for Unsaturation ]
• Dry Heating test burn with sooty flame

e.g.- Benzene, Phenol, Aniline, Naphthalene etc

Non Aromatic compounds

• May or may not Cyclic Structure
• May or may not Planar 
• Not Satisfy Huckle`s rule [ 4n + 2  = pi ]
• May or may not Resonance stabilized
• May or may not Positive Bromine test [ Test for Unsaturation ]
• Dry Heating test burn with non sooty flame

e.g.- Cyclopentane, Cyclobutene, Hexane etc

Stereoselective and Stereospecific Reaction

Stereoselective and Stereospecific Reaction

MCQ Multiple Choice Question Atomic Structure

Atomic Orbital

A. The Aufbau Principle states that?

1. Only two electrons can occupy an orbita

2. Electrons enter the lowest available energy level

3. Orbitals are regions in space around nucleus where one is likely to find an electron

4. Electrons remain unpaired if possible

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B. Which one of the following statements about orbitals is incorrect ?

1. Orbitals can hold two electrons provided they are spinning in the same direction

2. Orbitals are regions in space around nucleus where probability of finding of an electron is more

3. s, p, d and f orbitals are possible

4. Orbitals can hold up to two electrons

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C. Hund's Rule states that

1. Electrons enter the lowest available energy level

2. An orbital can hold up to two electrons

3. Electrons in similar energy orbitals remain unpaired as far as possible

4. Electrons enter the lowest available energy level

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D. Which of the following atoms has two unpaired electrons?

1. B

2. C

3. N

4. O

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E. Which one of the following statements about s orbitals is incorrect ?

1. They are found in all principal energy levels

2. They can only hold only one electron

3. They are spherical in shape

4. The maximum number of s orbitals in any principal level is 1

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F. Which one of the following statements about p orbitals is incorrect?

1. They are found in all principal energy levels

2. They have a dumb-bell shape

3. There are three types of p orbital

4. Each p orbital can hold up to two electrons

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G. Which one of the following statements about d orbitals is incorrect?

1. They are not found in the first two principal energy levels

2. They are associated with transition elements

3. There are 5 types of d orbital

4. d orbitals are filled before p orbitals in the same principal energy level

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H. Which one of the following statements is correct?

1. The 3d sub level is filled before the 4s sub level

2. The 3rd principal energy level only contains 8 electrons

3. Principal energy levels get closer together as they get further from the nucleus

4. Orbitals are always filled in numerical order

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I. The order of filling orbitals is

1. 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p

2. 1s, 2s, 2p, 3s, 3p, 3d, 4p, 3d

3. 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p

4. 4p, 4s, 3d, 3p, 3s, 2p, 2s, 1s

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J. Electrons enter the 4s sub-level before the 3d sub-level because

1. The 4s orbital has a lower energy

2. The 3d orbitals have a lower energy

3. The 4s orbital is spherical

4. There is only one 4s orbital and there are five 3d orbitals

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K. Which statement about chromium is incorrect?

1. Chromium is a transition metal

2. Chromium has an atomic number of 24

3. The electronic configuration of chromium atoms is 1s22s22p63s23p64s23d4

4. The electronic configuration of chromium atoms is 1s22s22p63s23p64s13d5

Willgerodt rearrangement