Question

Paradichlorobenzene, c6h4cl2 c 6 h 4 c l 2 , is a component of mothballs. A solution of 2. 00 g g in 22. 5 g g of cyclohexane boils at 82. 39 ∘c ∘ c. The boiling point of pure cyclohexane is 80. 70 ∘c ∘ c. Calculate kb k b for cyclohexane.

Answer 1

The value of kb of cyclohexane in the given question is; kb = 2.82 °C/m

Understanding Molality of a Solution

Molality of solution = (Number of moles of C₆H₄Cl₂)/(Mass of Cyclohexane)

Now;

Number of moles of C₆H₄Cl₂ = Mass/molar mass = 2g/147 g/mol

Number of moles of C₆H₄Cl₂ = 0.0136 mol

Molality of solution = 0.0136/(22.5 * 10⁻³ kg)

Molality of solution = 0.6 m

Now, to find kb for cyclohexane, we will use the formula;

T_b(solution) - T_b(solvent) = kb × molality of solution

Thus;

82.39 - 70 = kb * 0.6

kb = (82.39 - 70)/0.6

kb = 2.82 °C/m

Read more about Molality of Solution at; brainly.com/question/10278982