Aromatic Directive Influence

Q. Which of the following is most reactive towards electrophilic substitution reaction?

1. Benzene
2. Phenol
3. Toluene
4. Nitrobenzene

Q. Why nitro group is act as meta directing group in electrophilic aromatic substitution?

1. It decreases electron density at ortho and para position
2. It decrease electron density at meta position
3. It increases electron density at ortho and para position
4. None of the above

Q. In electrophilic substitution reaction of chlorobenzene, the ortho/para- directing ability of chlorine is due to its

1. Positive inductive effect (+I)
2. Negative inductive effect (-I)
3. Positive resonance effect (+R)
4. Negative resonance effect (-R)

Q.

Nitration is an example of aromatic electrophilic substitution and its rate depends upon the group already present in the benzene ring. Out of benzene and phenol, which one is more easily nitrated and why?

Q. Why is CH₃ reffered as electron donating group ? please explain..

Q.

Why does NH₃ form hydrogen bond but PH₃ does not?

Q.

Heterolysis of propane gives

1. Methyl and ethyl free radical

2. Methylium and ethyl free radical

3. Methyl anion and ethylium cation

4. Methylium and ethylium cation

Q. A group which deactivates the benzene ring towards electrophilic substitution but which directs the incoming group principally to the o - and p - positions is

1. -NH₂
2. -Cl
3. -NO₂
4. -C₂H₅

Q. Electrophilic substitution reaction in phenol take place at :

1. p-position
2. m-position
3. o-position
4. o- and p-position

Q.

Which of the following compounds would have the smallest value for $pKa$?

1. ${\mathrm{CHF}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{COOH}$

2. ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CF}}_2\mathrm{COOH}$

3. ${\mathrm{CH}}_2{\mathrm{FCHFCH}}_2\mathrm{COOH}$

4. ${\mathrm{CH}}_3{\mathrm{CF}}_2{\mathrm{CH}}_2\mathrm{COOH}$

Q. In the compound $C_6{H}_{5}Z$ which of the following has all predominantly ortho and para directing groups?

1. $Z=-N{O}_2,-Cl,-OH$
2. $Z=-OMe,-CN,-N{H}_2$
3. $Z=-NHCOC{H}_3,-Cl,-COOH$
4. $Z=-NHCOC{H}_3,-C{H}_3,-Br$

Q. The presence of the chlorine atom on benzene ring makes the second substituent enter at a position

1. ortho
2. meta
3. para
4. otho-para

Q.

Phenols and alcohols both have same -OH group but still phenols are sparingly soluble in water. This is because:

1. They have high molecular mass

2. They have non-polar aryl group.

3. They ionize readily to form more stable phenoxide ion

4. They have high boiling points.

Q. The relative rates of mononitration of $R-C_6{H}_5,$ where $R=-C{H}_3,-N{O}_2,-OH,-Cl$ are

1. $H_{3}C-C_6{H}_5>OH-C_6{H}_5>O_{2}N-C_6{H}_5>Cl-C_6{H}_5$
2. $OH-C_6{H}_5>Cl-C_6{H}_5>H_{3}C-C_6{H}_5>O_{2}N-C_6{H}_5$
3. $OH-C_6{H}_5>C{H}_3-C_6{H}_5>O_{2}N-C_6{H}_5>Cl-C_6{H}_5$
4. $OH-C_6{H}_5>H_{3}C-C_6{H}_5>Cl-C_6{H}_5>O_{2}N-C_6{H}_5$

Q. What is the decreasing order of reactivity among the following compounds towards aromatic electrophilic substitution? I. Chlorobenzene
II. Benzene
III. Anilinium chloride
IV. Toluene.

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

Q. 37. Which of the following is most reactive toward electrophilic aromatic substitution for halogen toulene or nitrobenzene

Q. Which is not the correct synthesis of m-bromonitrobenzene?

1. 
2. Both of these
3. 
4. None of these

Q. Which of the following option is incorrect regarding A?

1. A contains methyl group
2. A contains ethyl group
3. A contains -OH group
4. A contains a six membered ring

Q. Which of the following compounds will most readily undergo electrophilic aromatic substitution ?

1. 
2. 
3. 
4. 

Q. Arrange in order of decreasing trend towards aromatic electrophilic substitution reaction.
Chlorobenzene (I) , benzene (II) , anilinium chloride (III), toluene (IV).

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

Q.

Explain why is ortho nitrophenol more acidic than ortho methoxyphenol?

Q. Phenol undergoes electrophilic substitution more easily than benzene because :

1. $-OH$ group exhibits $+M$ effect and hence increases the electron density on the o- and p-positions.
2. oxocation is more stable than the carbocation.
3. both $\left(a\right)$ and $\left(b\right)$
4. $-OH$ group exhibits acidic character

Q.

Classify the following reactions in one of the reaction type studied in this unit.

(a) CH₃CH₂Br + HS^– → CH₃CH₂SH + Br^–

(b) (CH₃)₂ C = CH₂ + HCl → (CH₃)₂ ClC–CH₃

(c) CH₃CH₂Br + HO^– → CH₂ = CH₂ + H₂O + Br^–

(d) (CH₃)₃ C – CH₂ OH + HBr → (CH₃)₂ CBrCH₂CH₃ + H₂O

Q. The major product formed in the following reaction is

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

Q. Identify the correct order of reactivity in electrophillic substitution reactions of the following compounds

1. $1>2>3>4$
2. $4>3>2>1$
3. $2>1>3>4$
4. $2>3>1>4$

Q. In electrophilic substitution reaction of chlorobenzene, the ortho/para- directing ability of chlorine is due to its

1. Positive inductive effect (+I)
2. Negative inductive effect (-I)
3. Positive resonance effect (+R)
4. Negative resonance effect (-R)

Q. In an electrophilic aromatic substitution reaction, the nitro group is meta directing because of it:

1. decreases electron density at ortho and para positions
2. decreases electron density at meta position
3. increases electron density at meta position
4. increases electron density at ortho and para positions

Q. The most reactive compound towards electrophilic substitution is :

1. aniline
2. N-acetylaniline
3. nitorbenzene
4. anilinum chloride

Q. Which xylene is most easily sulphonated

1. Para
2. Meta
3. All at the same rate
4. Ortho

Q. What happens when $C{H}_{3}Br$ is treated with $KCN$?