Structure determination of organic compounds

Structure determination of organic compounds: by IR, UV-Vis, 1H & 13C NMR and Mass spectroscopic techniques.

YEAR JUN-2016 DEC-2015 JUN-2015 DEC-2014 JUN-2014 DEC-2013 JUN-2013 DEC-2012 JUN-2012 DEC-2011 JUN-2011
No.of questions appeared 5 5 5 5 4 4 5 5 4 6 8

1.Among the following, the compound that displays an IR band at 2150 cm-1 is….

ir-spectro-scopy-of-csir-ugc-net-chemistyry

 

2.In the 1H NMR spectrum of myrtenal, the two methyl groups are expected to display signals at (chemical shift values (δ)in ppm)

nmr-problems-csair-ugc-net-chemistry

 

3. In the UV-visible absorption spectrum of an α,β-unsaturated carbonyl compound, with increasing solvent polarity,

  1. n->π* transitions undergo hypsochromic shift, π->π* undergo bathochromic shift.
  2. n->π* transitions undergo bathochromic shift, π->π* undergo hypsochromic shift.
  3. bothn->π* and π->π* transitions undergo bathochromic shift.
  4. both n->π*

 

4.The correct structure of the compound, which shows following 13C NMR DEPT-135 data is 13C NMR DEPT-135: negative peaks at δ30.2, 31.9, 61.8, 114.7 ppm; positive peak at 130.4 ppm

spectroscopy-csir-net-gate-chemical-science-june-2016

 

 

5.A compound displays the following spectral data. The correct structure of the compound is

spectroscopy-csir-net-gate-chemical-science-june-2016

 

6.In the mass spectrum of 1, 2-dichloroeth-ane, approximate ratio of peaks at m/z values 98, 100, 102 will be

(1.) 3 : 1 : 1

(2.) 9 : 6 : 1

(3.) 1 : 1 : 2

(4.) 1 : 2 : 1

 

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