Question

The vapor pressure of pure methanol at 25 degrees Celsius is 127.2 mm Hg. If 12.20 g of potassium chloride are dissolved in 200.0 g of methanol, what is the vapor pressure of the solution?
A.123.9 mmHg
B.3.256 mmHg
C.104.3 mmHg
D142.7 mmHg

Answer 1

mols KCl = grams/molar mass = ?
mols methanol = grams/molar mass = ?
Xmethanol = mols methanol/total mols.
p(methanol) = i*X.methanol
i is 2 for KCl

Post your work if you get stuck.

Answer 2

I didn't get any of the answer choices
I got 1.95
It's .164 mol kcl
6.242 mol ch3oh
Then put the 6.242 over 6.406 and got .975
Then 2 x the .975

Answer 3

I gave you the wrong formula. Let me start over.

Answer 4

I don't get close to any of those answers.