II M.Sc - I Quiz: Organic Spectroscopy

1. Choose the incorrect statement.

• IR spectrum is a plot of wavenumber versus percentage transmittance

• Dipole moment of homonuclear diatomic molecules is zero

• Heteronuclear diatomic molecules are IR active

• Stretching vibration requires lower energy and occurs at lower frequency

Identify the base value of aromatic ester.

• 246 nm

• 217 nm

• 250 nm

• 230 nm

Calculate the λmax value of the following compound:

• 230 nm

• 245 nm

• 234 nm

• 240 nm

Which of the following transition takes place in CH3Br?

• σ-σ* and n-π*

• π-π* and n-σ*

• σ-σ* and n-σ*

• π-π* and n-π*

Mass spectrum is a plot of transmittance versus m/z. Say True or False.

• True

• False

Which of the following compound having higher stretching frequency?

• Alkanes

• Alkynes

• Alkenes

• Alkyl halides

Identify the typical energy of the electrons used to ionize specimens by Electron Ionization.

• 1000 eV

• 100 eV

• 70 e V

• 50 eV

What is the relation between wavenumber and the reduced mass in IR spectroscopy?

• Wavenumber is directly proportional to reduced mass

• Wave number is inversely proportional to reduced mass

• Wave number is independent of the reduced mass

• Wave number is directly proportional to square of reduced mass

Removal of a single electron from a molecule result in the formation of __________.

• Metastable ion

• Fragment ion

• Molecular ion

• Rearranged ion

The acidic proton of carboxylic acid is found at __________ in NMR.

• 0-2.0 ppm

• 2.5-4.5 ppm

• 8.0-9.0 ppm

• 10-12 ppm