Question

Match the following aqueous solutions with the appropriate letter from the column on the right. 1. 0.14 m Al(NO3)3 A. Lowest freezing point 2. 0.17 m Cr(CH3COO)2 B. Second lowest freezing point 3. 0.18 m (NH4)2CO3 C. Third lowest freezing point 4. 0.48 m Sucrose(nonelectrolyte) D. Highest freezing point

Answer 1

Tf = i*Kf*m

no of ions are increases freezing point is increases.

1. 0.14 m Al(NO3)3 ------------->D. Highest freezing point ( four particles ie i=4)

Tf = i*Kf*m

         = 4*1.86*0.14   = 1.0416C⁰

4. 0.48 m Sucrose(nonelectrolyte) --------> A. Lowest freezing point ( one particles i= 1)

   Tf = i*Kf*m

           = 1*1.86*0.48   = 0.8928C⁰

3. 0.18 m (NH4)2CO3 ---------------------> B. Second lowest freezing point ( 3 particles i=3, more molality than chromimum acetate)

      Tf = i*Kf*m

                 = 3*1.86*0.18 = 1.004C⁰

4. 0.17 m Cr(CH3COO)2 ------------------> C. Third lowest freezing point ( 3 partilecle i=3)

   Tf = i*Kf*m

          = 3*1.86*0.17   = 0.9486C⁰