Question

3.42 gn of sucrose is dissolved in 90 grms of water then the mole fraction of solute is ?

Answer 1

Answer:

The mole fraction of the solute is approximately 0.001996.

Explanation:

What is a mole fraction?

The mole fraction of a solute/solvent is the ratio of the moles of the solute/solvent to the total number of moles of solute and solvents.

It is denoted with the symbol χ (chi).

Mathematically, it can be written as:

$\chi_{A} = \frac{N_{A} }{N_{A} + N_{B}} or, \\\chi_{B}=\frac{N_{B} }{N_{A} + N_{B}}$
where N denotes the number of moles.

Calculation:

Wt. of sucrose = 3.42 gm
Molecular wt. of sucrose = 342 gm
∴ Moles of sucrose $= N_{A} = \frac{3.42}{342} = 0.01$

Wt. of water = 90 gm
Molecular wt. of sucrose = 18 gm
∴ Moles of sucrose $= N_{B} = \frac{90}{18} = 5$

∴ Mole fraction of the solute $= \chi_{A} = \frac{0.01}{0.01 + 5} = 0.001996$

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