Refractive Index - ORGANIC CHEMISTRY LAB

Question

A student attempts to separate a sample of cyclohexane and ethylbenzene by distillation. After the distillation the student obtains an n ²⁰_D of 1.4355 for what should be pure cyclohexane with a volume of 23.5 mL. Did the student obtain pure cyclohexane? If not, what volume of ethylbenzene is present in the distilled cyclohexane?

 

Refractive Indices (n²⁰_D)

cyclohexane (1.4266)

ethylbenzene (1.495)

 

Answer 1

(X)(1.4266) + (1-X)(1.495) = 1.4355

1.4266X + 1.495 - 1.495X = 1.4355

X = 0.8699

1-X = 0.1301

0.1301 x 23.5 ml = 3.06 ml of ethylbenzene