Question

74. The molality of 14 % (w/w) aqueous solution of
KOH is (Molecular mass of KOH= 56 u)
(1) 125/129 m
(2) 125/43 m
(3) 72/69m
(4) 165/76 m

Answer 1

Answer:

125/129m

Explanation:

beacausethe molality of 14% aqueous solutionof KOH is 125/129m

Answer 2

The correct answer is option (2) 125/43m

GIVEN

Mass% of KOH in the solution = 14%

TO FIND

The molality of the solution.

SOLUTION

We can simply solve the above problem as follows;

The mass% of KOH = 14%

This means that in 100 gram of solution the mass of KOH = 14 grams.

We know that,

Molality = moles of solute/mass of solvent in kg.

Mass of solvent = 100-14 = 86 grams = 0.086 kg

Moles of solute = 14/56 = = 0.25 Moles

Putting the values in the formula;

m = 0.25/0.086 = 125/43 M

Hence The correct answer is option (2) 125/43m

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