CBSE Class 12-science Answered

The elevation in boiling point for sugar solution is,

                                  ?T_b(sucrose) = (K_b X W_sucrose) / (M_sucrose X W_water )

Where, M_sucrose = 342 gm/mole

             W_water = 0.300 kg

Similarly, the elevation in boiling point for urea solution is,

                    ?T_b(urea) = (K_b X W_urea ) / (M_urea X W_water )

Where, M_urea = 60 gm/mole

             W_water = 0.1 kg

According to the question, ?T_b(sucrose) = ?T_b(urea)

     (K_b X W_sucrose) / (M_sucrose X W_water ) = (K_b X W_urea ) / (M_urea X W_water )

Or, W_sucrose / (342 X 0.300 ) = 3  / ( 60 X 0.1 )

W_sucrose  = 51.33 gm