Heterocyclic Aromatic Compounds

Q. Which of the following compounds is/are aromatic in nature?

1. 
2. 
3. 
4. 

Q. Which of the following compounds is unstable at room temperature?

1. 
2. 
3. 
4. All of the above

Q. Which of the following compound(s) is/are unstable at room temperature?

1. 
2. 
3. 
4. 

Q. Which of the following compound is aromatic in nature?

1. 
2. 
3. 
4. 

Q. Cyclobutadiene is said to be :

1. aromatic
2. aliphatic
3. anti-aromatic
4. none of the above

Q. Choose the correct statement(s) regarding the given compounds :

1. (a) is aromatic
2. (b) is non-aromatic
3. (a) is anti-aromatic
4. (b) is aromatic

Q. On the basis of molecular orbital treatment of various aromatic compounds, it has been observed that an aromatic compound must fulfill the following theoretical requirements. a) It must have an uninterrupted cyclic cloud of $\pi$-electrons above and below the plane of the molecule ( often called as $\pi$- cloud). Let us look what does this mean?
i) For the $\pi$-cloud to be cyclic, the molecule must be cyclic
ii) For the $\pi$-cloud to be uninterrupted, every atom in the ring must have a p- orbital
iii) For the $\pi$ -cloud to be formed, each p-orbital must be able to overlap with the $p-$orbitals on either side of it. Therefore, the
molecule must be planar. b) The $\pi$-cloud must contain an odd number of pair of $\pi$-electrons , $(4n+2)\pi$-electrons, where n is an integer. The stability order of the three compounds is:

1. $I>II>III$
2. $I>III>II$
3. $III>II=I$
4. $I=III>II$

Q. Which of the following statement is incorrect for the given compounds :

1. Compound (a) does not show tautomerism.
2. Compound (b) shows tautomerism
3. Compound (d) has a stable enol form
4. Compound (c) does not show tautomerism

Q. On the basis of molecular orbital treatment of various aromatic compounds , it has been observed that an aromatic compound must fulfil the following theoretical requirements.a) It must have an uninterrupted cyclic cloud of $\pi$ - electrons above and below the plane of the molecule ( often called as $\pi$ - cloud). Let us look what does this mean?
i) For the $\pi$ - cloud to be cyclic, the molecule must be cyclic.
ii) For the $\pi$ - cloud to be uninterrupted, every atom in the ring must have a p- orbital. iii) For the $\pi$ -cloud to be formed , each porbital must be able to overlap with the p-orbitals on either side of it. Therefore, the molecule must be planar .
b) The $\pi$ - cloud must contain and odd number of pair of $\pi$ - electrons , $(4n+2)\pi$- electrons, where n is an integer.
Cyclo- octatetraene is:

1. aromatic
2. non - aromatic due to (a) (ii)
3. non- aromatic due to (a) (iii)
4. non- aromatic due to (b)

Q. What is the electron sea model?

1. The model of metallic bonding where electrons float free in a sea of electrons around metal atoms.
2. Where electrons float free in a sea of salt water.
3. A model depicting the different bonds that electrons can make.
4. The model of metallic bonding where protons float free in a sea of electrons around metal atoms.
5. The model of metallic bonding where electrons are fixed in place in a sea of metal atoms.

Q.

Can aromatic compounds be heterocyclic?

1. True

2. False

Q.

Can aromatic compounds be heterocyclic?

1. False

2. True

Q. An aromatic compound follows (4n+2)$\pi$ rule, where n can not be

1. $\frac{1}{2}$
2. 3
3. 2
4. 1

Q.

Can aromatic compounds be heterocyclic?

1. True

2. False

Q. Assertion :If free redical chlorination of an achiral alkane generate a chiral carbon at alpha carbon, recemic mixture of alkyl chloride is always obtained. Reason: Halogenation occur at planar alkyl free radical.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is wrong but reason is correct.