The plot given below shows P - T curves (where, P is the pressure and T is the temperature) for two solvents X and Y and isomolal solutions of NaCl in these solvents. NaCl is completely dissociates in both the solvents. On the addition of equal number of moles of a non-volatile solute S in equal amount (in kg ) of these solvents, the elevation of boiling point of solvent X is three times that of solvent Y . The solut

Step-by-step solution

From the graph: For the solvent X , ∆ T bx = 2 ∆ T bx = m NaCl × K b x . . . i For the solvent Y , ∆ T by = 1 ∆ T b y = m NaCl × K b y . . . ii From the equations ( i ) and ( ii ), ⇒ K b x K b y = 2 For the solute S , i = 1 - α 2 ∆ T b x s = 1 - α 1 2 K b x ∆ T b y s = 1 - α 2 2 K b y Given: ∆ T b x s = 3 ∆ T b y s 1 - α 1 2 K b x = 3 × 1 - α 1 2 × k b y 2 1 - α 1 2 = 3 1 - α 2 2 α 2 = 0 .7 So, α = 0 .05