Chemistry Forum

A solution is prepared by 10 g of solid para-dichlorobenzene (C₆H₄Cl₂) in enough carbon tetrachloride to make a total of 350 mL of solution. The density of the resulting solution is 1.60 g/mL .

(a) Compute the molarity of the solution.

(b) Compute the weight % para-dichlorobenzene of the solution.

(c)Compute the molality of the solution.

(d) Compute the mole fraction of the solute.

(e) At 23℃ the vapor pressure of CCl₄ is 100 mm. Compute the vapor pressure of the solution at this temperature.

(f) When a different solution of C₆H₄Cl₂ is prepared, it is found to have a boiling point of 78.6℃. Given that \(K_b\) = 5.0 ℃-kg/mol and the boiling point of pure CCl₄ is 76.6℃, compute how many grams of solute are present in 100 grams of CCl₄.

I am working on this question and all of its sub-questions.

a) 0,194 M
b) 1,79% w.w
c) 0,12 mmol/kg
d) 0,019
The Rest its your job.

Thanks for your correct answers to questions (a), (b), (c) and(d).

My Computation work for answers to question (e) and (f).

My answer to (e)\(P_{CCl_4}=0.981 \times 100 mm=98.1 mm, P_{CCl_4}=\) Vapor pressure of solution

My answer to (f) \(\Delta T_{bp}=K_{bp}\times m; m= \frac{\Delta T_{bp}}{K_b}=\frac{78.6^\circ C-76.6^\circ C}{5.02^\circ C-kg/mol}=0.40 \)molal

Moles of C₆H₄Cl₂= 0.40 kg/mol × 0.100 kg = 0.040 mol C₆H₄Cl₂

Grams of C₆H₄Cl₂ = 0.040 mol C₆H₄Cl₂ × 147 g/mol =5.88 g C₆H₄Cl₂

Ok