Question

If mole fraction of methanol in acetone is 0.2 then
molality of methanol in the solution will be
(1) 4.3 m
(2) 5.8 m
(3) 2.0 m
(4) 9.2 m​

Answer 1

Explanation:

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Answer 2

Answer:

Concept:

The number of moles of the same component in a solution divided by the total moles of all the solution's constituents is known as the mole fraction of that component. The amount fraction is another name for the mole fraction.

Explanation:

Let molality of a solution be p.

Moles of solute=  $\frac{Mass of solute}{Molar mass of solute}$

=$\frac{1000}{58.08}$ = 17.21

Mole Fraction of solute =$\frac{Molality}{molality + moles of solute}$

=$\frac{p}{p + 17.21}$

mole fraction of  methanol in acetone=0.2

0.2=$\frac{p}{p + 17.21}$

0.2(p+17.21)=p

3.442=p-0.2p

p=$\frac{0.8}{3.442}$

p=4.3

∴Molality=4.3 m

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