JEE Main202229 Jul 2022Evening ShiftChemistrySolutionsActual
1 . 80   g of solute A was dissolved in 62 . 5   cm 3 of ethanol and freezing point of the solution was found to be 155 . 1   K . The molar mass of solute A is gmol - 1 . [Given: Freezing point of ethanol is 156 . 0   K . Density of ethanol is 0 . 80   g   cm - 3 . Freezing point depression constant of ethanol is 2 . 00   K   kg   mol - 1 ]
Correct answer
0
Step-by-step solution
Given Mass of C 2 H 5 OH = 62 . 5 × 0 . 8 = 50   g Mass of solute = 1.80 g Depression in freezing point ∆ T f   =   156 . 0 - 155 . 1   =   0 . 9   K We know that the depression in freezing point ΔT f = K f × m 0 . 9 = 2 × 1 . 8 × 1000 M w × 50 M w = 2 × 1 . 8 × 1000 0 . 9 × 50 = 80