osmolarity problem?

Question

ok you have 0.1 M NaNO3

which has a greater osmolarity...

0.1 M NaCl or 0.1 M NaNO3?

and please explain in details.

osmolarity = molarity x i

i stands for particles

I know that the value of i in NaCl is 2 therefore
osmolarity = 0.1 M x 2 = 0.2 osmolarity

but what about for NaNO3?
if there are three elements, where would the 3 go? I desperately need help on this:(

Answer 1

NaCl -> Na(+) + Cl(-)
NaNO3 -> Na(+) + NO3(-)

Both anions are conjugate bases of strong acids and therefore you don't need to worry about hydrolysis.

So you'll have practically the same i and the same osmolarity.

In reality i could be different depending on the attractive forces between the ions, but it is quite reasonable to assume that for equal concentrations of these two salts the i is not very different.
(Don't forget that i is also a function of concentration)

and by the way i is the Van't Hoff coefficient

Answer 2

2nd. remember the osmolarity depends on the number of particles, and if we have the same amount of each substance, we have more particles in the second, that is made up with 3 elements instead of the two of NaCl. Look for the formula and calculate it yourself...

Osm=v.g.M
M= mols /liter