A gas chromatography was used for separating a mixture that contained 3 hydrocarbons (ortho-xylene, meta-xylene, and para-xylene). Internal diameter of the column was 3.9 mm and the length was 3.6 m. Conditions of the first trial are:

Room pressure = 695.1 mm Hg

Room temperature = 23.0 ^oC

Inlet pressure = 65.0 psi

Column temperature = 350 ^oC

He gas flow rate = 30.3 mL/min (measured using a soap bubble flow meter at the column outlet)

Conversions: partial pressure of water at 22.1 ^oC = 19.8 mm Hg; 760 mm Hg = 14.7 psi; absolute pressure = 273.15 ^oC.

Compound	Retention Time tR (min)	Peak Width W (min)
ortho-xylene	8.90	0.563
meta-xylene	7.83	0.498
para-xylene	7.36	0.467

The time, t_M, for the unretained peak to elute was 1.65 min.

a) Selectivity () for meta-xylene and para-xylene

b) During the experiment, baseline resolution was not achieved between meta-xylene and para-xylene. Calculate the number of theoretical plates are needed to achieve resolution?

c) Calculate the corrected retention volume for ortho-xylene.

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