pls help to answer questions below , For 4a) how do i know if its a positive or negative deviation curve?

CONFIDENTIAL (Question 4) (a) Sketch the kon-ideal vapour pressure-composition curve f element X and nitrous acid, HNO2 where the composition of azeotropic mixture is (40% X at 40C and the boiling point of is higher than (HND) Explain the vapour pressure of each composition and distillation process of above mixture using the curve (20 marks) (b) How does the melting point of CO2 change with pressure? What does this indicate about the relative density of solid CO2 versus liquid CO2