back to directory
NEET CHEMISTRYOrganic Chemistry – Some Basic Principles and Techniques Medium

Question

The correct order of dipole moments for molecules NH3_3, H2_2S, CH4_4 and HF is:

A

CH4_4 > H2_2S > NH3_3 > HF

B

H2_2S > NH3_3 > HF > CH4_4

C

NH3_3 > HF > CH4_4 > H2_2S

D

HF > NH3_3 > H2_2S > CH4_4

Step-by-Step Solution

  1. CH4_4 (Methane): It has a symmetrical tetrahedral geometry. The vector sum of the four C-H bond moments cancels out completely, resulting in a net dipole moment of 0 D.
  2. HF (Hydrogen Fluoride): Fluorine is the most electronegative element (EN = 4.0). The electronegativity difference between H and F is very high, and the molecule is linear. This results in the highest dipole moment among the group (≈1.78\approx 1.78 D).
  3. NH3_3 (Ammonia): Nitrogen is more electronegative (EN = 3.04) than Sulphur. The molecule is pyramidal. The orbital dipole of the lone pair reinforces the resultant dipole of the N-H bonds, leading to a high dipole moment (≈1.47\approx 1.47 D).
  4. H2_2S (Hydrogen Sulphide): Sulphur (EN = 2.58) is less electronegative than Nitrogen and Fluorine. While bent, the lower electronegativity difference results in a smaller dipole moment (≈0.95\approx 0.95 D) compared to HF and NH3_3.
  5. Conclusion: The decreasing order is HF > NH3_3 > H2_2S > CH4_4.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Organic Chemistry – Some Basic Principles and Techniques . Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYOrganic Chemistry – Some Basic Principles and Techniques correctdipolemomentsmolecules

More Organic Chemistry – Some Basic Principles and Techniques Questions

View all

Which one of the following pairs is isostructural (i.e., having the same shape and hybridization)?

A.$\text{BCl}_3$ and $\text{BrCl}_3$
B.$\text{NH}_3$ and $\text{NO}_3^-$
C.$\text{NF}_3$ and $\text{BF}_3$
D.$\text{BF}_4^-$ and $\text{NH}_4^+$
MediumSolve

Among the following, isoelectronic species are:

A.$CO_{2}, NO_{2}$
B.$NO_{2}^{-}, CO_{2}$
C.$CN^{-}, CO$
D.$SO_{2}, CO_{2}$
EasySolve

Which one of the following pairs of species have the same bond order?

A.$\text{CO}$, $\text{NO}$
B.$\text{O}_2^-$, $\text{CN}^-$
C.$\text{CN}^-$, $\text{NO}^+$
D.$\text{N}^+$, $\text{CN}^+$
MediumSolve

In a regular octahedral molecule, $MX_{6}$, the number of $X–M–X$ bonds at 180º is:

A.Two
B.Six
C.Four
D.Three
EasySolve

Which of the following pairs of ions are isoelectronic and isostructural?

A.CO₃²⁻, SO₃²⁻
B.ClO₃⁻, CO₃²⁻
C.SO₃²⁻, NO₃⁻
D.ClO₃⁻, SO₃²⁻
MediumSolve

Which orbital does the additional electron occupy when $O_{2}$ is converted to the $O_{2}^{-}$ ion?

A.$\pi$ orbital
B.$\sigma^{*}$ orbital
C.$\sigma$ orbital
D.$\pi^{*}$ orbital
MediumSolve

A species that does not exhibit paramagnetism is:

A.$N_{2}^{+}$
B.$O_{2}^{-}$
C.$CO$
D.$NO$
MediumSolve

The total number of $\pi$-bond electrons in the following structure is:

A.4
B.8
C.12
D.16
EasySolve

Why 32,000+ students choose TopperSquare

Everything you need to crack NEET

15,000+ Chapter MCQs

Physics, Chemistry, Biology — chapter-wise, topic-wise practice

AI Performance Analytics

Know your weak topics. Get a personalised study plan.

Full NEET Mock Tests

180 questions, timed, with detailed score analysis

PYQ Sets 2010–2024

15 years of past papers with solved explanations

Start Practising Free

No credit card · 30-second signup · Free forever plan included

This neet chemistry practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice chemistry sets →

Explore more subjects:Physics MCQs•Chemistry MCQs•Biology MCQs•Botany MCQs•Zoology MCQs•NEET Mock Tests•NEET PYQs