Experimentally it is observed that This equation implies that the activity coefficient i (or its logarithm)

Experimentally it is observed that 

This equation implies that the activity coefficient γ_i (or its logarithm) is weakly dependent on mole fraction near the pure component limit. Since we also know that γ_i → 1 as x_i → 1, this equation further implies that the activity coefficient is near unity for an almost pure substance. 

a. Show that this equation is satisfied by all the liquid solution models discussed in Sec. 9.5. 

b. Show that since this equation is satisfied for any substance, we also have

Transcribed Image Text:

lim xi-1 In i əxi T,P = 0 for any species i