Question

4. In each of the following groups of substances, circle the one that has the given property. Give proof of answer and how your determined your answer (7pts each) Appreciate help for this question

Highest boiling point: HBr, Kr or Cl2

Lowest freezing point: N2, CO, or CO2

. Highest boiling point: CH4, CH3CH3, or CH3CH2CH3

Answer 1

Answer – In this one there are given the groups of substances and need to circle the one that has the given property.

1)Highest boiling point – Cl₂

We know the highest boiling point is for those one has more and strong intermolecular forces, so HBr has dipole-dipole force and Kr has only dispersion force. For Cl₂ there is Cl-Cl bond has stronger than H-Br, since there is no any dipole-dipole interaction, so there is bond between Cl-Cl is stronger than H-Br, so the highest boiling point is for Cl₂

2) Lowest freezing point – N₂

The lowest freezing point for N₂ and there is very close to this freezing point for CO also. The CO freezing point is -205^oC and for N₂ it is -210^oC. So both has nearly same, but N₂ has lowest. CO₂ has freezing point is -56.6^oC.

3) Highest boiling point - CH3CH2CH3

We know in the same functional group the boiling point trend is like as the molar mass increase boiling point also increase, so propane has more molar mass than methane and ethane, so propane has more boiling point.