Question - 2.5 - Calculate
(b) molarity and
(c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g mL –1.
Given, 20% (mass/mass) aqueous solution of KI.
This means 20 gm of KI is dissolved in 80 gm of water.
Molar mass of KI = 39 + 127 = 166 g mol – 1
Mass of solute (W B) = 20 gm
Mass of solvent (WA ) = 80 gm
Molar mass of solute (M B)= 166 g mol – 1
Density of the aqueous KI = 1.202 g mL – 1
(a) Now, Molality of KI
(b) Molarity of KI
Thus, molarity of KI = 1.45 M
(c) Number of moles of KI
Number of moles of H2O
Now, Mole fraction of KI
Thus, mole fraction of KI in the given solution = 0.265