[michelleoruge33]

Which of the following statements about interionic and intermolecular forces are true ?

a) The binding forces in a MgSO4 solid lattice structure are ion-ion interactions

b) The forces binding the crystal lattice structure of NaCl are weaker than the forces between H2O molecules in water.

c) The intermolecular forces between HCl(g) molecules are ion-ion interactions

d) The strongest intermolecular forces between OF2(g) molecules are dipole-dipole forces

e) A large number of hydrogen bonds in a substace can result in intermolecular forces that are stronger than normal dipole-dipole interactions

a) Here is how i approached the first one. Mg is an ion but S and O are not (but are anions). So i believe that the interactions between them are ION to Anion Interactions. False

b) This is false because they both form an octet of 8 valence electrons. False

c) The forces between HCL are ION-ION interactions and they form an octet group so Cl get's the 8 electrons that it wants. True

d) This is correct because they do have London dispersion but, dipole-dipole moments are stronger (but don't last that long). It can't be Hydrogen forces because their are no Hydrogen's. True

e) I believe this is also true. Because Hydrogen forces are stronger than Lodon forces and dipole-dipole forces. True

a) false
b) false
c) true
d) true
e) true

But it say's that i am wrong why is that?

[Arctic-Nation]

a) There's no such thing as an anion that is not an ion. (And I probably should be shot for constructing such a sentence.) However, the gravest error in your answer is your assumption that oxygen and sulfur are loose atoms (or ions), when they are bound together into a sulfate anion. The correct answer is: Mg cation - sulfate anion interactions, thus, ionic bonding.

b) Hydrogen and oxygen in water also have closed shells, so this doesn't really explain the difference. Fact is that lattice ion-ion interactions are much stronger (easily two orders of magnitude) than hydrogen bonds.

c) HCl gas does not exist in a dissociated state (there is no proton acceptor or Lewis base present). Intermolecular interactions are mainly weak hydrogen bonding.

d) Oxygen difluoride has a permanent dipole moment, thus the main interactions are dipole-dipole based. London dispersion forces are much smaller.

e) is correct.