Question
Chemistry Question on Mole concept and Molar Masses
If 1.202 g mL−1 is the density of 20% aqueous KI, determine the molality of KI.
A
(A) 1.51 m
B
(B) 2.53 m
C
(C) 3.54 m
D
(D) 2.55 m
Answer
(A) 1.51 m
Explanation
Solution
Explanation:
Molar mass of KI=39+127=166 g mol−120% aqueous solution of KI means 20 g of KI is present in 100 g of solution.Therefore, Mass of KI=20 gThat is, 20 g of KI is present in (100−20)g of water =80 g of waterWe know that:Molality of the solution = Moles of KI Mass of water in kg=Mass of KIMolar Mass of KI Mass of water in kg=201660.08 m=1.506 m=1.51 mHence, the correct option is (A).