Tutorial 2.4 - Intermolecular Forces

Question 1

Suggest a suitable solvent to dissolve hexane (C6H14). [1]

Answer 1

• any organic liquid with C>4

- eg. benzene hexane is a common non-polar solvent but cannot be used for this Q

Question 2

Explain why methanethiol (CH3SH) cannot form hydrogen bonds. [2]

Answer 2

• Sulphur is less electronegative than oxygen
• S-H bond is not polar enough (to attract S: from another molecule
• DON’T JUST SAY because there is no N, O or F present!*

Question 3

Explain why methanol molecules are polar [2]

Answer 3

• O-H is polar bond

- molecule is not symmetrical

Question 4

Describe the hydration of the chloride ions formed when HCl dissolves in water. [2]

Answer 4

• δ+ H atom (of H2O) attracted to…

- (Full) negative charge of Cl—

Question 5

If asked what type of bonding something it and it is hydrogen bonding, in brackets put…

Answer 5

(type of permanent dipole-dipole force)