Question

Which of the following is most basic in nature?
A) $N{H_3}$
B) $C{H_3}N{H_2}$
C) ${\left( {C{H_3}} \right)_2}NH$
D) ${C_6}{H_5}N{\left( {C{H_3}} \right)_2}$

Answer 1

Hint: We know that the basicity of the substance increases as the number of +I groups increases while the basicity decreases as the number of (-I) groups increases. As we realize that the alkyl bunches are electron-giving gatherings and they have a positive inductive impact. Subsequently the alkyl bunches in the methylamine expands the electron thickness of the nitrogen molecule in the amine bunch makes them more fundamental substances.

Complete step by step answer:
We have to remember that the basicity of amines relies upon the accessibility of the solitary pair of electrons accessible for donation. Electron delivering bunches like methyl increases the basicity of amines by expanding the electron thickness over nitrogen which encourages the gift of a solitary pair of electrons. Hence option C is correct.
We know that ammonia is a weak base as it has a lone pair of electrons in its nitrogen but it is stronger base than phenylamine and weaker base than methyl and ethyl amine. Hence Option (A) is incorrect.
We must remember that the methyl amine has only one electron delivering group whereas in case of dimethyl amine there are two electron delivering groups. Therefore, methyl amine have lower basicity value than the dimethyl amine. Therefore, the option B is incorrect.
Now coming to the option D,
The phenyl group is an electron-withdrawing group (-I) and the lone pair of nitrogen at amine group delocalizes within the phenyl ring which reduces the electron density and makes the substance least basic. Hence option (D) is incorrect.

So, the correct answer is Option C.

Note: Let’s we discuss about the concept of inductive effect as,
Inductive impact implies the polarization of the sigma bond because of electron pulling in and electron delivering impact of a contiguous molecule.
\[C{H_3}^{\delta + + } - C{H_2}^{\delta + } - C{l^{\delta - }}\]
We have two types of inductive effect namely positive inductive effect (+I) and negative inductive effect (-I).
Positive inductive effect:
An atom or a group which attracts electrons towards itself less than a hydrogen atom is known as an electron-donating group and they are said to have a positive inductive effect (+I).
Negative inductive effect:
An atom or a group which attracts electrons towards itself more strongly than a hydrogen atom is known as an electron attracting group and they are said to have a negative inductive effect (-I).