NTA Abhyas JEE Main2020ChemistrySome Basic Concepts of ChemistryPractice
The mole fraction of a solute in a solution is 0.1. At 298 K, molarity of this solution is the same as its molality. Density of this solution at 298 K is 2.0 g c m - 3 . The ratio of the molecular weights of the solute and solvent, M W s o l u t e M W s o l v e n t , is
Correct answer
9
Step-by-step solution
X s o l u t e X s o l v e n t = 0.1 0.9 = 1 9 W s o l u t e W s o l v e n t × M s o l v e n t M s o l u t e = 1 9 ...(i) W s o l u t e + W s o l v e n t = W s o l u t i o n = d e n s i t y × v o l u m e W s o l u t e + W s o l v e n t = 2 × V ...(ii) Molarity = molality n s o l u t e V s o l u t i o n = n s o l u t e W s o l v e n t W s o l v e n t = V s o l u t i o n = W s o l u t e + W s o l v e n t 2 2 W s o l v e n t = W s o l u t e + W s o l v e n t W s o l u t e = W s o l v e n t ...(iii) Using equation (i) a