Yu have four related molecules xa mw 140 xb mw 100 xc mw

Question

You have four related molecules, XA (mw =140), XB (mw = 100), XC (mw = 80) and XD (mw = 120). None of the four can hydrogen bond. During the evaporation of XB, |?T| = 7.2^oC. During the evaporation of XD, |?T| = 4.7^oC. What would be the expected |?T| during the evaporation of XA?

Available answers:

• 10.1^oC 
•  4.7^oC 
•  2.5^oC 
•  7.2^oC