Aromatic Compounds

Q.

Compound with molecular formula ${\mathrm{C}}_3{\mathrm{H}}_6\mathrm{O}$ can show-

1. Both positional isomerism and metamerism

2. Metamerism

3. Positional isomerism

4. Functional group isomerism

Q. How many $\sigma$ and $\pi$ bonds are present in the following molecule?
(𝑎) $HC\equiv CCH=CHC{H}_3$
(𝑏) $C{H}_2=C=CHC{H}_3$

Q. Correct order of resonance energy of following compounds:

1. II > I > IV > III
2. II > IV > I > III
3. I > II > III > IV
4. II > I > III > IV

Q.

What are the necessary conditions for any system to be aromatic?

Q. Cyclobutadiene is said to be:

1. Aliphatic
2. Anti-aromatic
3. None of the above
4. Aromatic

Q. Which of the following is not an aromatic compound?

1. 
2. 
3. 
4. 

Q.

Which of the following are aromatic?

1. 

2. 

3. 

4. 

Q. Explain the shape of $Br{F}_5$.

Q. Among the following, the no. of aromatic compound(s) is/are:

Q. How many $\pi$ electrons are there in the given compound?

1. 2
2. 4
3. 6
4. 8

Q.

Explain why the following systems are not aromatic?

(i)

(ii)

(iii)

Q. Which of the following is a heterocyclic aromatic compound?

1. 
2. 
3. 
4. None of the above

Q.

Keto-enol tautomerism is not observed in :

1. C₆H₅COCH₂COCH₃

2. CH₃COCH₂COCH₃

3. C₆H₅COC₆H₅

4. C₆H₅COCH=CH₂

Q. Though nitrogen exhibits $+5$ oxidation state, it does not form pentahalide. Give reason.

Q. Identify the compound that cannot exhibits tautomerism:

1. Phenol
2. 2-butene
3. Lactic acid
4. 2-pentanone

Q.

Maximum enol content is in:

1. $H-\stackrel{\underset{||}{O}}{C}-C{H}_3$

2. $C{H}_3-\stackrel{\underset{||}{O}}{C}-C{H}_3$

3. $C{H}_3-\stackrel{\underset{||}{O}}{C}-C{H}_2-\stackrel{\underset{||}{O}}{C}-C{H}_3$

4. $Ph-\stackrel{\underset{||}{O}}{C}-C{H}_2-\stackrel{\underset{||}{O}}{C}-Ph$
   

Q. how to differentiate between aromaticity, anti-aromaticity, non-aromaticity?

Q.

How are cyclic compounds classified?

Q. Which of the following is aromatic in nature?

1. 
2. 
3. 
4. All of these

Q. Secondary amine is?

1. An orgnic compound with two $N{H}_2$ groups
2. A compound with two carbon atoms and an $-N{H}_2$ group
3. A compound with an $N{H}_2$ group on the carbon atom in number 2 position
4. A compound in which two of the hydrogens of $N{H}_3$ have been replaced by organic groups.

Q. Which of the following is not an aromatic compound?

1. 
2. 
3. 
4. 

Q. Dipole moment of which ketone is maximum?

1. 
2. 
3. 
4. 

Q. Arrange the following alcohols in decreasing order of the ease of ionization under acidic conditions.

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

Q. Decreasing order of acidic strength of the following compounds is :

1. $\left(z\right)>\left(y\right)>\left(x\right)$
2. $\left(y\right)>\left(z\right)>\left(x\right)$
3. $\left(z\right)>\left(x\right)>\left(y\right)$
4. $\left(x\right)>\left(z\right)>\left(y\right)$

Q. According to Huckel rule, an aromatic compound must possess:

1. $(4n+1)\pi$ electrons
2. $(4n+2)\pi$ electrons
3. $(2n+2)\pi$ electrons
4. $4n\pi$ electrons

Q. Ordinarily the barrier to rotation about a carbon-carbon double bond is quite high but in compound P double bond between two rings was observed by NMR to have a rotational energy barrier of only about 20 cal/mol, showing that it has lot of single bond character.
The reason for this is

1. Double bond having partial triple bond character because of resonance
2. Double bond undergo flipping
3. Double bond is having high single bond character because of aromaticity gained in both three and five membered rings.
4. +I effect of $n{C}_3{H}_7$ groups makes double bond having partial single bond character.

Q. 7 Phenols can be distinguished from ethyl alcohol by all reagents except (1) NaOH (2) FeCl3 (3) Br2/H2O (4) Na

Q. Which of the following species is the least stable?

1. 
2. 
3. 
4. 

Q. Which of the following is anti-aromatic in nature?

1. 
2. 
3. 
4. 

Q. The skeletal structure of $C{H}_{3}COOH$ as shown below is correct, but some of the bonds are shown incorrectly. Write the correct Lewis structure for acetic acid.