Question

Physical Chemistry- Topic - Raults' Law/Henry's Law/Mole Factions

Determine which is more poisonous using Physical Chemistry

Two identical glasses filled with 100 mL the same liquid, one with 1g of NaCl and the other with 1g of iocane powder. Iocane is colorless, order less, and dissolves isntantly into many liquids.Iocane is "the most deadly poison known to man". It is not ionic but has a carbon-iodine bond.

To help you are allowed to only run one test on the two glasses.

Change Hvap = 40.8kJ/mol

Change Hfus = 6.1 kj/mol

kboil = 0.51?

kf = 1.85?

Show and explain the test you would do to detrmine which is more poisonous

Answer 1

NaCl is a strong electrolyte (i.e. an ionic compound), which completely dissociates into sodium ion (Na⁺) and chloride ion (Cl^-).

Hence, 1 g of NaCl completely dissociates in the 100mL liquid contained in the glass.

Therefore, the mole fraction of NaCl is very high in the solution.

Now, iocane, even though containing a carbon-iodine bond, is not an ionic compound and it will not dissociate into the corresponding carbonium ion (R₃C⁺) and iodide ion (I^-).

Hence, 1 g of iocane will not dissolve, as a result it will not dissociate in the 100 mL liquid contained in the glass.

Therefore, the mole fraction of iocane is very low (i.e. negligible) in the solution.

Conclusion: The solution containing 1 g of NaCl is more poisonous than that containing 1 g of iocane.