MULTIPLE CHOICE QUESTION WITH ANSWER



MCQ ON IR SPECTROSCOPY 


1.   Bending vibrations include all following except

              (a)  Rocking 

               (b)  Stretching

               (c)  Twisting 

               (d)  Wagging

2.  For calibration of wave number scale in IR _______ is used.

              (a)  Holmium filter 

              (b)  Polystyrene film

              (c)  Polyvinyl film 

              (d)  None


3.  For obtaining IR radiation Nernst filament should be heated to _______°C.

              (a)  500–1000 

              (b)  1000–1500

              (c)  2000–2500 

              (d)  1000–1800

4.  CO2  not identified by IR spectroscopy it’s due to

               (a)  CO2  has no dipole moment although C=O is polar

               (b)  CO2 has no dipole moment since C=O is non-polar

               (c)  Optical activity of the system

              (d)  Both a and b

5.  The region of an infra-red spectrum where many  absorptions take place is known as the __________

(a)  Thumbprint region

(b)  Handprint region 

(c)  Footprint re gion 

(d)  Finger print region


  6.  Bolometer is made up of

(a)  Two dissimilar metals

(b)  Non-centro-symmetric crystal

(c)  Fused mixture of metal oxide

(d)  Pt strip in evacuated vessel

 

7.  Which is used in calibration of IR instrument?

(a)  TMS 

(b)  Glass

(c)  Metal halide 

(d)  Polystyrene

 

8.  What is selection rule for a molecule to become IR active in I.R. spectroscopy?

(a)  Must show change in dipole moment

(b)  Must show dipole moment

(c)  Must show change in magnetic moment

(d)  Must show magnetic moment

 

9.  In IR Spectroscopy the changes in electronic energy is always associated with charges in

(a)  Rotational energy

(b)  Vibrational and rotational

(c)  Vibrational, rotational and translational

(d)  All

 

  10.  In Raman spectroscopy physical properties measured is

(a)  Absorption of radiation

(b)  Scattering of radiation

(c)  Emission of radiation

(d)  Rotation of radiation

 

11.  Globar sources is made of

(a)  Earth oxide Zirconia

(b)  Mercury

(c)  Silicon dioxide

(d)  Silicon carbide

 

12.  Gratings are generally prefer red over prisms for   dispersive IR because

(a)  Better resolution is possible

(b)  Linear dispersion is achieved

(c)  Gratings are resistant to attack by water

(d)  All are correct

 

13.  Which of the following requires the most energy in IR?

(a)  Wagging 

(b)  Asymmetric bend

(c)  Twisting 

(d)  Asymmetric stretch

  14.  Lasers are nowadays used as radiation source in visible and IR regions because

(a)  It emits highly monochromatic light.

(b)  It emits coherent light

(c)  Little or no spreading of radiation as it propagates

(d)  All the above are correct

 

 15.  In far infrared region the radiation sources use is

(a)  Incandescent lamp  

(b)  Nernst glower

(c)  Globar sources 

(d)  Mercury Arc

 

16.  In XY2  molecule vibration of atom is take place in same plan and only bond angle is change then it is called

(a)  Stretching vibration

(b)  Bending vibration

(c)  Scissoring vibration

(d)  Rocking vibration

 

17.  SiC rod heated to a high temperature is used as

(a)  Source of light in IR

(b)  Detector in IR

(c)  Source of light in UV

(d)  Source of light in florimetry

 

18.  The region mostly used for IR spectroscopy is

(a)  Near IR 

(b)  Mid-IR

(c)  Far IR   

(d)  Very far IR


19.  Hexachlorobutadiene is preferred over Nujol as a mulling agent because

(a)  It is non toxic

(b)  It does not giv e C–H vibration bands

(c)  It is transparent ov er IR range

(d)  It has ver y high boiling point.

 

20.  The band width in IR _____ due to H bonding.

(a)  Increases

(b)  Decreases

(c)  Remains unchanged

(d)  Cannot be predicted

 

21.  Homo molecular molecules are IR inactive because

(a)  They cannot give vibrational spectra

(b)  They have only stretching vibrations

(c)  They have no bending vibrations

(d)  The dipole moment does not change during  vibration

 

22.  Which of the following transitions will require more wavelengths?

(a)  Vibrational 

(b)  Rotational

(c)  Electronic

(d)  Vibrational – Rotational

  23.  Which of the following prisms will you use for IR spectroscopy?

(a)  Glass prism

(b)  Fused silica prism

(c)  Prism coated with NaCl

(d)  All can be used

 

24.  IR spectroscopy generally used to determine

(a)  Molecular structure

(b)  Functional group

(c)  Number of protons

(d)  All of the above


25.  Pressed disk techniques for the sample preparation in IR involve the use of

(a)  Salt plate  

(b)  Nujol

(c)  KBr 

            (d)  All of the above 

1. b

2. b

3. d

4. a

5. d

6. d

7. d

8. a

9. c

10. b

11. d

12. a

13. d

14. d

15. d

16. a

17. a

18. b

19. c

20. a

21. d

22. b

23. c

24. b

25.c

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