JEE Main202225 Jun 2022Evening ShiftChemistrySolutionsActual
Solute A associates in water. When 0 . 7 g of solute A is dissolved in 42 . 0 g of water, it depresses the freezing point by 0 . 2 ° C . The percentage association of solute A in water, is [Given: Molar mass of A = 93 g mol - 1 . Molal depression constant of water is 1 . 86 K kg mol - 1 ]
Options
- A50 %
- B60 %
- C70 %
- D80 %
Correct answer
D. 80 %
Step-by-step solution
Depression in freezing point, ΔT f = iK f × m 2 . 0 = ix 1 . 86 × 7 × 1000 93 × 42 2 . 0 = i 3 . 33 i = 0 . 6 i = 1 + 1 n - 1 β 0 . 6 = 1 + 1 2 - 1 β β = 0 . 8 % β = 80 Hence, the percentage association of solute A in water is 80.