A solution of sodium sulfate contins 92g of Na^{+}  ions per kilogram of water.The molality of Na^{+} ions in that solution in mol\, \, kg^{-1} is:

  • Option 1)

    12

  • Option 2)

    4

  • Option 3)

    8

  • Option 4)

    16

Answers (1)
A admin

 

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.

 

 

Molecular Formula -

The molecular formula shows the exact number of different types of atoms present in a molecule of a compound.

- wherein

For glucose, empirical formula is CH2O .its molar mass is 180 gram.

n = molar mass/empirical formula mass = 180/30=6

Hence molecular formula= C6H12O6

 

 

Mole Concept -

One mole is the amount of a substance that contains as many particles or entities as there are atoms in exactly 12 g (or 0.012 kg) of the 12C isotope.

- wherein

one mole = 6.0221367 X 1023   

as we know that no. of moles=\frac{mass}{molar mass}=\frac{94gram}{23gram/mol}=4mol

so, molality =\frac{moles}{weight of solution\left ( kg \right )}=\frac{4mol}{1}

n= 4 mol/kg

 

 


Option 1)

12

Option 2)

4

Option 3)

8

Option 4)

16

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