Question

6. Solvent passes through a column in 3.0 min but solute requires 9.0 min. The volume of stationary phase is 1/10 of the volume of the mobile phase. Find the partition coefficient, K, for this system.

   A) 20 B) 5.0 C) 1.0 D) 0.20 E) 0.05

Answer 1

First we have to find the capacity factor which is denoted by k^'

So, k^' = t_r - t_m / t_m

Where t_r is residence time of solute = 9 min

t_m is residence time of solvent = 3 min

So,  k^' = t_r - t_m / t_m

k^' = 9 min - 3 min / 3 min

k^' = 2

Partition coefficient K = k^' * (V_m / V_s )

Where, V_m is volume of mobile phase

V_s is volume of stationary phase

It is given that volume of stationary phase is 1/10 of the volume of the mobile phase;

So, K = k^' * (V_m / V_s )

K = 2^' * (V_m / 0.1 V_m )

K = 2^' / 0.1

K = 20

So, option A is correct, 20