In q 73 option 3 is not correct order. Also explain with reason why other are other order are correct.
Dear student,
In (3) Lone pair of nitrogen in aniline is involve in resonance, hence less available for donation. Thus it is less basic then formamide.
due to this reason it is a incorrect option.
In (1) CH3 group at ortho position creates steric hindrance, NH2 group after accepting a proton becomes -NH3+ which moves out of plane due to steric repulsions and hence the positive charge is not delocalized making the compound less stable. So the equilibrium is towards the left, making it less basic.
More substitution at ortho position more will be steric hindrance, hence less basic will be the structure.
In (2) The alkyl group shows +I effect and hence the more is the number of alkyl group present with nitrogen, the lesser is the -I effect of nitrogen. Thus, NH3 shows more -I effect than NR3.
The decreasing order of -I effect.
In (4)
In (3) Lone pair of nitrogen in aniline is involve in resonance, hence less available for donation. Thus it is less basic then formamide.
due to this reason it is a incorrect option.
In (1) CH3 group at ortho position creates steric hindrance, NH2 group after accepting a proton becomes -NH3+ which moves out of plane due to steric repulsions and hence the positive charge is not delocalized making the compound less stable. So the equilibrium is towards the left, making it less basic.
More substitution at ortho position more will be steric hindrance, hence less basic will be the structure.
In (2) The alkyl group shows +I effect and hence the more is the number of alkyl group present with nitrogen, the lesser is the -I effect of nitrogen. Thus, NH3 shows more -I effect than NR3.
The decreasing order of -I effect.
In (4)
Formic acid is more acidic than benzoic and acetic acid, due to the presence of only an H atom and no methyl or phenyl group. Phenyl group is weakly electron donating that increases the negative charge on carboxylate group and decreases the acidity of benzoic acid as compared to formic acid. Since methyl group is a strong electron releasing group as compared to phenyl, acetic acid is the weakest.
Regards