Chemistry question?

[BxSci_CY]

What will be the boiling point of a solution when two moles of magnesium chloride is added to 100 grams of water?

What is it possible answer and how did you get it?
Can anyone else answer this? I'm getting different answers...

[RHineland]

deltaT<sub b> = K<sub b> * molality of sol'n

first, we need to look at the table for the K<sub b> of the solvent

K<sub b> = molal-boiling point elevation constant of H2O

molality = mol solute / kg solvent

molality = 2 mol MgCl2 / 0.100 kg H2O = 20 molal

therefore deltaT = 20K<sub b>

then, the new boiling point is

new boiling point = deltaT + original boiling point of solvent

original boiling point of solvent = 100 C

new boiling point = 20K<sub b> + 100

sorry, i can't find K<sub b> for water

if you know it, just substitute it

=)

[Simonizer1218]

Actually, you need to take into account the van't Hoff factor which for MgCl2 would be 3 (1Mg and 2 Cl). So then you can use the formula
delta T = iKm where i=van't Hoff; K is the water constant; m=molality.
So molality = 2moles/0.1kg = 20 molal
K = 0.512 for water
i = 3
delta T = (3)(0.512)(20) = 30.72 degrees
So boiling point would 130.72 degrees centigrade