Question

The molality of aqueous solution of any solute having mole fraction 0.25 is

Answer 1

molality = 18.51 molal

plz refer to the attachment above

Answer 2

Answer:

The molality of an aqueous solution measured is $18.51 molal$.

Explanation:

Given,

The mole fraction of solute, $X_{A}$ = $0.25$

The given aqueous solution's molality =?

As we know,

• Mole fraction of the solute + Mole fraction of the solvent = 1

Therefore,

• The mole fraction of the solvent, $X_{B}$ = 1 - mole fraction of the solute
• The mole fraction of the solvent, $X_{B}$ = $1-0.25$ = $0.75$

Now, the solvent is aqueous, i.e., $H_{2}O$.

Thus, the molar mass of $H_{2}O$, $M_{B}$ = $18g/mol$

As we know, the molality of the solution can be calculated by the equation given below:

• Molality = $\frac{X_{A} \times 1000}{X_{B} \times M_{B} }$

After putting the given values in the equation, we get:

• Molality = $\frac{0.25\times 1000}{0.75 \times 18 }$
• Molality = $18.51 molal$

Therefore, the molality of the aqueous solution = $18.51 molal$.