Which position will be attacked most rapidly by the nitronium ion (-NO₂)⁺ when the compound undergoes nitration with HNO₃/H₂SO₄ :-

1. A

2. B

3. C

4. D

Which one of the following undergoes nucleophilic aromatic substitution at the fastest rate?
(1) 

(2) 

(3) 

(4) 

Some meta-directing substituents in aromatic substitution are given.
Most deactivating group among the following is: 

1. –SO₃H

2. –COOH

3. –NO₂

4. –C≡N

Among cyclohexanol (I), acetic acid (II), 2, 4, 6-trinitrophenol (III) and phenol (IV) the correct order of decreasing acidic character will be:

Following is the list of some aromatic compounds. Select the correct sequence of decreasing order of reactivity for electrophilic aromatic substitution reaction using the answer codes given below:

a. ${\mathrm{C}}_6{\mathrm{H}}_5 - \mathrm{OH}$

b. ${\mathrm{C}}_6{\mathrm{H}}_5 - {\mathrm{CH}}_3$

c. ${\mathrm{C}}_6{\mathrm{H}}_5 - {\mathrm{NO}}_2$

d. ${\mathrm{C}}_6{\mathrm{H}}_5 - \mathrm{CHO}$

Answer codes :

1. a d b c

2. c d b a 

3. a b d c

4. a b c d