Spectroscopy topics include: Mass Spectroscopy, Visible Spectroscopy, & Infrared Spectroscopy. Spectroscopy is a field of study that measures and interprets electromagnetic spectra. It can also be defined as the study of color as generalized from visible light to all bands of the electromagnetic spectrum.   There are three basic types of spectroscopy: Atomic absorption spectroscopy (AAS) Atomic emission spectroscopy (AES) Atomic fluorescence spectroscopy (AFS)  AAS includes methods such as: Infrared (IR) spectroscopy Ultraviolet-visible (UV-Vis) spectroscopy  Here are some types of... Show more

Spectroscopy topics include: Mass Spectroscopy, Visible Spectroscopy, & Infrared Spectroscopy.

Spectroscopy is a field of study that measures and interprets electromagnetic spectra. It can also be defined as the study of color as generalized from visible light to all bands of the electromagnetic spectrum.
 

There are three basic types of spectroscopy:
Atomic absorption spectroscopy (AAS)
Atomic emission spectroscopy (AES)
Atomic fluorescence spectroscopy (AFS) 

AAS includes methods such as:
Infrared (IR) spectroscopy
Ultraviolet-visible (UV-Vis) spectroscopy 

Here are some types of spectroscopy:

Ultraviolet spectroscopy: Uses the selective absorbance of ultraviolet radiation by various substances. It is especially useful in investigating biologically active substances such as compounds in body fluids, and drugs and narcotics.
Infrared spectroscopy: Uses the infrared region of the electromagnetic spectrum. This region of the spectrum has a longer wavelength and lower frequency than visible light. IR spectroscopy can be used to identify and study chemicals.
Raman spectroscopy: Uses the inelastic scattering of photons by molecules, which results in the molecules gaining vibrational energy and the photons losing it. It is commonly used in the branch of chemistry to provide a fingerprint by which molecules can be identified.
Nuclear magnetic resonance (NMR) spectroscopy: An advanced characterization technique. It is used to determine the molecular structure at the atomic level of a sample. 
 

Related Test: Organic Chemistry Practice Test: Nuclear Magnetic Resonance

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Organic Chemistry Practice Test: Spectroscopy

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25 Questions

1. A compound C₈ H₆ decolorizes Br₂ in CCl₄ and gives a white precipitate with Tollen’s reagent. It has sharp band at 3300 cm^-l and weak bands at 3085, 2110 cm^-l. What is this compound?

Phenyl acetyleneOctenePhenyl propylenePhenyl ethylene

2. Who discovered the mass spectrometer?

J. J ThomsonWalter KaufmannErnest O. LawrenceFrancis Aston

3. Which species of the following is used to bombard with the sample for which mass spectroscopy has been performed?

Alpha particlesElectronsProtonsNeutrons

4. Which of the following main component of mass spectroscopy deal with resolving the ions into their characteristics mass components according to their mass-to-charge ratio?

Detector SystemIon SourceAnalyzer tubeAnalyzer

5. The ultraviolet spectrum of benzonitrile shows a primary absorption band at 224 nm. If a solution of benzonitrile in water, with a concentration of 1x 10^-4 molar, is examined at a wavelength of 224 nm, the absorbance is determined to be 1.30. The cell length is 1 cm. What is the molar absorptivity of this absorption band?

2.3 x 1043.3 x 1044.3 x 1041.3 x 104

6. Separation of ions in mass spectrometer take place on the basis of which of the following?

ChargeMassMass to charge ratioMolecular weight

7. Which of the following statement is false for mass spectroscopy?

This technique basically studies the effect of ionizing energy on moleculesParticle are characterized by their mass to charge ratios (m/z) and relative abundancesMass spectroscopy is used to identify unknown compounds within a sample, and to elucidate the structure and chemical properties of different moleculesThis technique can be used on all state of matter

8. On which factors the vibrational stretching frequency of diatomic molecule depend?

TemperatureForce constantMagnetic fieldAtomic population

9. What is the number of vibrational degrees of freedom in C₆H₅CH₃?

40391518

10. Which of the following comparison is correct for solvent shift on the n –>π* transition of acetone?

H20 < CH30H < C2H50H < CHC13 < C6H14H20 > CH30H > C2H50H > CHC13 > C6H14H20 > CH30H < C2H50H < CHC13 < C6H14H20 = CH30H = C2H50H = CHC13 = C6H14

11. Which of the following molecules will not show infrared spectrum?

CH4H2HCIH20

12. Which type of ionic species are allowed to pass through the slit and reach the collecting plate?

Negative ions of all massesNegative ions of the specific masspositive ions of the specific massPositive ions of all masses

13. For HCI = 1.63 x 10^-27 kg, the observed frequency = 2890 or v = 8.67 x 10¹³ Hz. What is the force constant K?

4.83 m dyn Å-1483 μm-14.83 dyn Å-18.43 dynes cm-1

14. What is the correct order of λmax for n –> π* transition for the R-CN, R-NO₂, and R-N=N-R?

R-CN > R-NO2 < R-N=N-RR-CN > R-NO2 > R-N=N-RR-CN = R-NO2 = R-N=N-RR-CN < R-NO2 < R-N=N-R

15. The frequency of vibration of a bond is a function of which factor?

Masses of the atoms involved in bondingForce constant of the bondBond orderForce constant of the bond and Masses of the atoms

16. The ultraviolet spectrum of benzonitrile shows a secondary absorption band at 271 nm. If a solution of benzonitrile in water, with a concentration of 1×10^-4 molar solution is examined at 271 nm, what will be the absorbance reading (ℇ = 1000) and what will be the intensity ratio, I_O/I, respectively?

0.2, 2.260.3, 3.260.4, 4.260.1, 1.26

17. What is the relation between restoring force, f to the displacement q in Hooke’s law?

f = kqf = -kqf = kq2f = -kq2

18. What is the order of decreasing vibrational frequency for C — Cl, C — Br, C — C, C — O and C — H?

C-Br, C- Cl, C-C, C-O, C-HC-H, C-C, C-O, C- Cl, C-BrC-O, C-H, C-Br, C- Cl, C-CC- Cl, C-Br, C-C, C -H, C-O

19. In which unit Force constant is not expressed?

Dynes cm-1Nm-1dyne Å-1kp

20. An organic compound Q exhibited the following spectral data obtained by mass spectroscopy.
IR: 1760 cm^–1
1HNMR: chemical reference (ppm): 7.2 (IH, d, 16.0 Hz), 5.1 (IH, m), 2.1 (3H, s), 1.8 (3H, d, J = 7.0 Hz)
¹³CNMR chemical reference (ppm): 170 (carbonyl carbon). What is compound Q?

21. What is the relation between wave number of IR absorption and the reduced mass?

Wave number is inversely proportional to reduced massWave number is independent of the reduced massWave number is directly proportional to square of reduced massWave number is directly proportional to reduced mass

22. Why ketenes absorb in IR at a very high frequency (2150 cm^-1)?

The more s character in a bond, the stronger it isInner C is sp2 hybridizedInner C is sp3 hybridizedThe inner C is sp hybridized

23. Which compound having molecular formula C₅H₁₀ shows absorption at 1380 cm^-1?

Pentyne2-Methyl-1-buteneMethylcyclobutaneCyclopentane

24. What is the correct order of λmax for n –> σ* transition?

R-OH < R-NH2 < R-SHR-OH > R-SH > R-NH2R-OH > R-NH2 > R-SHR-OH < R-SH < R-NH2

25. What is the wavelength range for UV spectrum of light?

700 nm to 1 mm10 nm to 400 nm400 nm – 700 nm0.01 nm to 10 nm