Question

a water solution of aspirin has osmotic pressure of 12.7 torr. what is the molarity of aspirin in the solution (R=0.08206 Latm/mol

Answer 1

we know that the osmosis equation is, π = i M R T

π = (osmotic pressure)=12.7 torr

i=(van't hoff factor of aspirin)= it is assume to be 1.

M=(molarity)=we hve to calculate it.

R=(Universal gas constant)=0.08206 L atm mol¯¹ K¯¹

T=(temprature,here it is assumed as room temprature)=25 degree celsius=298 kelvin.

from the above formula we can derive, M= (π ) /(i R T)

putting the value we get, M=(12.7 torr / 760.0 torr/atm)/(1*0.08206 L atm mol¯¹ K¯¹ *298 kelvin.)

=0.00068334752 molar(answer).