CBSE Class 12-science Answered

calculate molality,molarity and mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g/ml? M of KI = 145 g/mol and H2O =18g /mol.

Giv20% means 100g of solution has 20g.  mass of solvent = 100-20 = 80, Mass of soln= 100, d = 1.202 g mL  volume of solution= 83.19 mL, moles of KI = 20/145=.1379 moles

Molarity= 1000X.1379/83.19= 1.65M

molality= 1000x.1379/80= 1.723 m

moles of KI=.1379 and water = 80/18=4.444 total no. of moles = 4.5819

mole fraction of KI = .1379/ 4.5819= .0300