Solutions - Intext Questions and Answer - class 12 chemistry

Solution:

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 (W_A ) = 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