Check Here for Important Questions on MOLECULAR SPECTROSCOPY (Download PDF)!

By Renuka Miglani|Updated : August 30th, 2021

Hi Gradians,

It will not be a new thing for you if we say that Gradeup is considered as the synonym for success. For the past 5 years, At BYJU'S Exam Prep we have been promoting talented candidates of the CSIR-NET category to the path of success. BYJU'S Exam Prep has been an integral part of the preparation journey of many Aspirants.

As we all know, the CSIR-NET exam is very near and there is no time left for revision. At this point of time, you must be seeking some ready-made authentic short revision notes or some important questions to practice just before the exam. How will you react if you get all these study materials at one place? It will be beneficial for you at this time right! We at BYJU'S Exam Prep comes up with the Most Important Questions of Molecular Spectroscopy for Chemical Sciences to help you score good marks which have been meticulously designed by our experienced subject-matter experts.

So what are you waiting for? Scroll down the article below and start study for the CSIR NET Exam, these questions will be fruitful during last-minute revision to fetch more marks in the exams. Students can also download it as a PDF file and save it for future purposes.

We have been providing short study notes for the Chemical Science subject which can be checked here. We have experienced immense love and support from all of you through these short notes in the CSIR-NET category, and we hope you all continue to support us in the same way!

Hi Gradians,

It will not be a new thing for you if we say that Gradeup is considered as the synonym for success. For the past 5 years, At BYJU'S Exam Prep we have been promoting talented candidates of the CSIR-NET category to the path of success. BYJU'S Exam Prep has been an integral part of the preparation journey of many Aspirants.

As we all know, the CSIR-NET exam is very near and there is no time left for revision. At this point of time, you must be seeking some ready-made authentic short revision notes or some important questions to practice just before the exam. How will you react if you get all these study materials at one place? It will be beneficial for you at this time right! We at BYJU'S Exam Prep comes up with the Most Important Questions of Molecular Spectroscopy for Chemical Sciences to help you score good marks which have been meticulously designed by our experienced subject-matter experts.

So what are you waiting for? Scroll down the article below and start study for the CSIR NET Exam, these questions will be fruitful during last-minute revision to fetch more marks in the exams. Students can also download it as a PDF file and save it for future purposes.

We have been providing short study notes for the Chemical Science subject which can be checked here. We have experienced immense love and support from all of you through these short notes in the CSIR-NET category, and we hope you all continue to support us in the same way!

Molecular Spectroscopy - Most Important Questions! (Download PDF)

1. If the internuclear distance (i.e bond length) of a carbon monoxide molecule is 1.13 Å, then calculate the energy in eV. The atomic masses are: 12C = 1.99 × 10–26 kg; 16O = 2.66 × 10–26 kg.

A. 4.76×10-4

B. 4.76×10-3

C. 2.78×10-4

D. 2.78×10-3

2. The pure rotational (microwave) spectrum of the gaseous molecule CN consists of a series of equally spaced lines separated by a distance of 3.7978 cm–1. Calculate the internuclear distance (i.e., equilibrium bond length) of the molecule. The molar masses are: 12C = 12.011 mol–1 and 14N = 14.007 g mol–1.

  1. 130 pm
  2. 121 pm
  3. 117 pm
  4. 290 pm

3. The pure rotational (microwave) spectrum of gaseous HCl consists of a series of equally spaced lines separated by 20.80 cm–1. Calculate the internuclear distance of the molecule. The atomic masses are:

 1H = 1.673 × 10–27 kg and 35Cl = 58.06 × 10–27 kg.

  1. 135 pm
  2. 129 pm
  3. 146 pm
  4. None of the above

4. Calculate the approximate value of Jmax for a rigid diatomic molecule for which the rotational constant is 1.566 cm–1 at 300 K.

  1. 10
  2. 12
  3. 11
  4. 8

5. For HCl, the fundamental vibrational frequency is 2,890 cm–1. Calculate the force constant of this molecule. The atomic masses are 1H = 1.673 × 10–27 kg; 35Cl = 58.06 × 10–27 kg.

  1. 500 Nm-1
  2. 483 Nm-1
  3. 789 Nm-1
  4. 654 Nm-1

6. A sample was excited by the 4358 Å line of mercury. A Raman line was observed at 4447 Å. Calculate the Raman shift in cm–1.

  1. 580
  2. 760
  3. 460
  4. 640

7. At what wavelength in Å would the anti-stokes line appear in the Raman spectrum of the sample excited by the 4358 Å line of mercury. A Raman line was observed at 4447 Å.

  1. 6238
  2. 4272
  3. 5678
  4. 3456

8. In a certain fluxional molecule, two groups that are interchanged by the conversion have vibrational absorption bands observed at 1650 cm–1 and 1655 cm–1. Calculate by using the Heisenberg uncertainty principle, the minimum lifetime of the states for which the separate absorptions could be distinguished.

  1. 0.2 ps
  2. 0.9 ps
  3. 0.5 ps
  4. 0.8 ps

9. Determine the NMR frequency (in MHz) of the proton (1H) in a magnetic field of intensity 1.4092 tesla, given that gN = 5.82 and μN = 5.05 × 10–27 J T–1.

  1. 90
  2. 75
  3. 60
  4. 25

10. At the coalescence temperature 331 K, the frequency separation between the two NMR signals of N, N-dimethylacetamide is 10.85 Hz. Determine the value of the rate constant for the first-order chemical exchange of the two methyl groups.

  1. 24.1 s-1
  2. 32.1 s-1
  3. 42.5 s-1
  4. 34.8 s-1

Solutions

Solution 1: 

 

Solution 2: 

Solution 3: 

 

Solution 4: 

Solution 5: 

Solution 6: 

Solution 7: 

Solution 8: 

Solution 9: 

Solution 10: 

 

ANSWER KEY

  1. A
  2. C
  3. B
  4. D
  5. B
  6. C
  7. B
  8. C
  9. C
  10. A

Download Important Questions on Molecular Spectroscopy - Download PDF Here

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Posted by:

Renuka MiglaniRenuka MiglaniMember since Jan 2021
This article was curated by Renuka Miglani who is an Associate Manager at BYJU'S Exam Prep (CSIR-NET). A PostGrad with an educational background in Nutrition Science, she is an ardent reader & writer. Loves to impart knowledge to students. Being from a Nutrition Science background, she is well aware of the opportunities available and has hared the same in the above article. Stay tuned for more interesting articles from her which will be beneficial for your career.
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