Arrange the following in increasing orde | Class 12 Chemistry Chapter Amines, Amines NCERT Solutions

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter Amines. This page offers a step-by-step solution to the specific question from Exercise 1, Question 4: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 4:

Arrange the following in increasing order of their basic strength:

(i) C2H5NH2, C6H5NH2, NH3, C6H5CH2NH2 and (C2H5)2NH

(ii) C2H5NH2, (C2H5)2NH, (C2H5)3N, C6H5NH2

(iii) CH3NH2, (CH3)2NH, (CH3)3N, C6H5NH2, C6H5CH2NH2.

Answer:

(i) Considering the inductive effect of alkyl groups, NH3, C2H5NH2, and (C2H5)2NH can be arranged in the increasing order of their basic strengths as:

NH3 2H5NH2 <(C2H5)2NH

Again, C6H5NH2 has proton acceptability less than NH3. Thus, we have:

C6H5NH2 3 2H5NH2 <(C2H5)2NH

Due to the - I effect of C6H5 group, the electron density on the N-atom in C6H5CH2NH2 is lower than that on the N-atom in C2H5NH2, but more than that in NH3. Therefore, the given compounds can be arranged in the order of their basic strengths as:

C6H5NH2 3 2H5NH2 C6H5CH2NH22H5NH2<(C2H5)2NH

 

(ii) Considering the inductive effect and the steric hindrance of the alkyl groups, C2H5NH2, (C2 H5)2NH2, and their basic strengths as follows:

C2H5NH2 <(C2 H5)3N <(C2 H5)2NH

Again, due to the - R effect of C6H5 group, the electron density on the N atom in C6H5 NH2 is lower than that on the N atom in C2H5NH2. Therefore, the basicity of C6H5NH2 is lower than that of C2H5NH2. Hence, the given compounds can be arranged in the increasing order of their basic strengths as follows:

C2H5NH2 2 H5NH2 <(C2 H5)3N <(C2 H5)2NH

 

(iii) Considering the inductive effect and the steric hindrance of alkyl groups, CH3NH2, (CH3)2NH, and (CH3)3N can be arranged in the increasing order of their basic strengths as:

(CH3)3N 3NH2 (CH3)2NH

In C6H5NH2, N is directly attached to the benzene ring. Thus, the lone pair of electrons on the N - atom is delocalized over the benzene ring. In C6H5CH2NH2, N is not directly attached to the benzene ring. Thus, its lone pair is not delocalized over the benzene ring. Therefore, the electrons on the N atom are more easily available for protonation in C6H5CH2NH2 than in C6H5NH2 i.e., C6H5CH2 NH2 is more basic than C6H5NH2.

Again, due to the - I effect of C6H5 group, the electron density on the N - atom in C6H5CH2NH2 is lower than that on the N - atom in (CH3)3N. Therefore, (CH3)3N is more basic than C6H5CH2NH2. Thus, the given compounds can be arranged in the increasing order of their basic strengths as follows.

C6H5NH2 6H5CH2NH2 <(CH3)3N 3NH2 <(CH3)2NH


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Amines.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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Comments

  • Anonymous
  • Oct 08, 2019

The answers of (I)st and (ii)nd are wrong apart from the (iii)rd one. Kindly update the answers with the correct order


  • Mahi
  • Jul 22, 2019

Recheck your answers plz...


Add Comment

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 4: Arrange the following in increasing order of their basic strength: (i) C2H5NH2, C6H5NH2, NH3, C6H....