Question

3. Why halogenated compounds like CCl4 act as a quencher? Explain the mechanism 4. Which of the following molecules may show infrared absorption spectra: a) H2 b) HC c) CO2 d) H20? 5. How many normal modes of vibrations are there in: a) H2 b) HCIc) CO2 d) H20?

Answer 1

3. Why halogenated compounds like CCl4 act as a quencher? Explain the CC4 can quench a free radical reaction by forming trichloromethyl CC13) radical as shown below mechanism CCla-Cl R. free radical ㅡㅡ나> .CCI+R-CI (quenching of free radical) + Mechanism 4 Which of the following molecules may show infrared absorption spectra: a) H2 HCIc) CO2 ) H20 ? A molecule will be IR active, if it's dipole momemt is not equal to zero H2 being a homonuclear diatomic molecule, it's dipole moment is zero so IR inactive HCI being a hetronuclear diatomic molecule, it's dipole moment is nonzero so IR active CO: being a linear triatomicmolecule, it's dipole moment is zero so IR inactive H:O being a nonlinear triatomic molecule, it's dipole moment is nonzero so IR active 5 How many normal modes of vibrations are there in: a) H2 b)HCI c) CO2d) H2O? If a molecule contains N' atoms, total number of vibrational modes For linear molecule it is (3N-5) and For non linear molecule it is (3N.6) HC1, a liear molecule, will have 3 x 2-5-1 degrees of vibrational freedom, or modes H2, a linear molecule, will have 3 x 2-5-1 degrees of vibrational freedom, or modes. CO2, a linear molecule, will have 3 x 3-5-4 degrees of vibrational freedom, or modes. H20, a non-linear molecule, will have 3 x 3-6 3 degrees of vibrational freedom, or modes.