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Solve! Calculate the molality of a solution containing of Acetic acid in Ethanol if the mass of solute = 10g and the density of Ethanol = 0.789 gmL-1.

Calculate the molality of a solution containing of Acetic acid in Ethanol if the mass of solute =  10g and the density of Ethanol = 0.789 gmL-1.

  • Option 1)

    0.2112

  • Option 2)

    0.2012

  • Option 3)

    0.1992

  • Option 4)

    0.2002

 
Answers (1)
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As we have learnt

 

Molality -

Molality (m) = (number of moles of solute)/(mass of solvent in kg)

 

- wherein

It is defined as the number of moles of solute present in 1 kg of solvent. It is denoted by m.

 

 

Mass of solute = \frac{10}{60} = \frac{1}{6}

Volume of ethanal = 1 L

Weight of ethanal = 1000 x 0.789 = 789g

Molality = \frac{mass\;of\;solute}{mass\;of\;solution} = \frac{10}{60\times\frac{789}{1000}} = 0.2112m


Option 1)

0.2112

Option 2)

0.2012

Option 3)

0.1992

Option 4)

0.2002

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