When 4.31 g of a nonelectrolyte solute is dissolved in water to make 635 ml of solution at 28 °c, the solution exerts an osmotic pressure of 945 torr. what is the molar concentration of the solution?

Molar concentration is 0.050 M

Explanation:

Osmotic pressure -

Osmotic pressure is pressure applied  to stop the flow of solvent across a semipermeable membrane, from its high concentration to  its low concentration , it is a type of colligative property , i.e. , it depends on the number of moles of solute.

Osmotic pressure can be calculated from the formula -

π = CRT

π = Osmotic pressure ( in atm )

C = molarity of the solution

R = universal gas constant ( 0.082 L.atm / K.mol )

T = temperature ( Kelvin )

From the question ,

π = 945 torr

since,

760 torr = 1 atm

1 torr = 1 / 760 atm

945 torr = 1 / 760 * 945 atm

945 torr = 1.24 atm

Temperature = T = 28°C

(adding 273 To °C to convert it to K)

T = 28 + 273 = 301 K

Using the equation of osmotic pressure,

π = CRT

C = π / RT

putting the

C = 1.24 atm / 0.082 L.atm / K.mol * 301 K

C = 1.24 / 24.68

C = 0.050 M

Hence,

The Molar concentration is 0.050 M.  

im not exactly sure but i think its b!