Question

Statement 1: Acetanilide is more active than aniline toward electrophilic substitution reaction
Statement 2: The activating effect of \[{\text{NHCOC}}{{\text{H}}_3}\] is less than that of amino group
A.Statement 1 is true, statement 2 is true; statement 2 is correct explanation for statement 1
B.Statement 1 is true, statement 2 is true; statement 2 is not correct explanation of statement 1
C.Statement 1 is true, statement 2 is false
D.Statement 1 is false, statement 2 is true

Answer 1

Hint: Amino group has more \[ + {\text{M}}\] effect as compared to \[{\text{NHCOC}}{{\text{H}}_3}\] . During electrophilic substitution reaction, electrophile attacks at site that have more electron density.

Complete step by step answer:
If any group or atom tends to donate or withdraw electrons via resonance from a ring or carbon chain, such an effect is known as mesomeric effect. The groups or atoms which donate its electron are known as \[ + {\text{M}}\] groups. The groups or atoms with electron withdrawing tendency are known as \[ - {\text{M}}\] effect groups. The Mesomeric effect is more pronounced at ortho and para positions of the benzene ring. Groups with \[ + {\text{M}}\] effect cause increase in electron density at ortho and para positions, whereas groups with \[ - {\text{M}}\] effect cause decrease in electron density at ortho and para positions.
Electrophilic substitution reactions are those reactions in which one electrophile substitutes other species. As electrophile are electron deficient species, attacking electrophile attacks at the site with more electron density. \[ + {\text{M}}\] group increases the electron density in the ring, so it will also increase the reactivity of the ring towards electrophilic substitution. On the other hand, groups with \[ - {\text{M}}\] effect causes decrease in electron density in the ring, it will also decrease reactivity of the ring towards electrophilic substitution.
Both \[ - {\text{N}}{{\text{H}}_2}{\text{ and }} - {\text{NHCOC}}{{\text{H}}_3}\] that is amide and acetamide is having \[ + {\text{M}}\] effect. They both will increase the reaction of the ring toward electrophilic substitution reaction. But due to more \[ + {\text{M}}\] effect of -\[ - {\text{N}}{{\text{H}}_2}{\text{ than }} - {\text{NHCOC}}{{\text{H}}_3}\] aniline is more reactive than acetanilide toward electrophilic substitution reaction. This is because the electrons are less available for donation in \[{\text{NHCOC}}{{\text{H}}_3}\] due to resonance. Yes, the activating effect of \[{\text{NHCOC}}{{\text{H}}_3}\] is less than that of the amino group.

Thus the correct option is D.

Note:
Molecules with \[ + {\text{M}}\] group decrease acidic strength because they tend to destabilise the anion formed after removal of hydrogen ion or proton. The molecules with \[ - {\text{M}}\] group increases acidic strength by stabilising the anion formed.