PHM20703 REVISION

In the normal phase HPLC, the

• mobile phase is polar and the stationary phase is non-polar.

• mobile phase is non-polar and the stationary phase is polar.

• eluent strength is increased by adding a less polar solvent to the mobile phase.

• eluent strength is increased by adding a more polar solvent to the mobile phase.

Which of the following statement is TRUE regarding loop injector in SFC?

• Injected stream is dissolved in diluent flow.

• Requires high pressure pump to inject feed solution.

• Permits injection of feed solution directly onto column.

• Used mostly for preliminary tests of column performance.

Which of the following is INCORRECT regarding deuterated solvent in an NMR sample?

•   Stabilize the magnetic field.

•  Set the chemical shift reference.

•   Obtain good field homogeneity across the sample.

Which of the following compound with molecular formula C₃H₆Cl₂ exhibits only one signal in the ¹H NMR spectrum?

• 1,1-Dichloropropane.

• 1,2-Dichloropropane.

• 1,3-Dichloropropane.

• 2,2-Dichloropropane.

The ¹H NMR spectrum of CH₃OCHCICH₂Cl will exhibit

• a three proton triplet, one proton triplet and a two proton triplet.

• a three proton singlet, one proton triplet and a two proton doublet.

• a three proton singlet, one proton singlet and a two proton doublet.

• a three proton doublet, one proton singlet and a two proton doublet.

What is the range of stretching vibration in IR spectrum of hexane?

• 1480 – 1440 cm^-1.

• 2260 – 2100 cm^-1.

• 2950 – 2840 cm^-1.

• 3100 – 3000 cm^-1.

________ bending vibration is when two atoms move up and below the plane with respect to the central atom.

• Rocking

• Twisting

• Wagging

• Scissoring