A problem in volumetric calculations in Chemistry

[Wrichik Basu]

Homework Statement

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The density of a 2.05 molar solution of acetic acid is 1.02g/ml. The Molality of the solution is:

(a) 1.14 mole/kg
(b) 3.28 mole/kg
(c) 2.28 mole/g
(d) 0.44 mole/kg

Homework Equations

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The Attempt at a Solution

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I tried it out very simply using unitary method:

Molality is the number of moles of solute in 1000g of solvent.

1.02g acetic acid has 1ml volume.

So, 1000g acetic acid has 1000/1.02 ml volume.

1000ml acetic acid soln. has 2.05 moles of the acid.

So, 1000/1.02 ml has 2.05/1.02 moles = 2moles.

This answer doesn't match with any answer. Where am I wrong?

 

[Borek]

You need to calculate mass of the solvent at some point, don't you?

 

[Wrichik Basu]

You need to calculate mass of the solvent at some point, don't you?

Yes, true. A bit more...