im given the refractive index values of two - isobutyl bromide (1.3785) and isobutyl chloride (2.4368).

Question

the solution's refractive index is 1.3931.

determine the molar composition (%).

im not sure how to get the concentrations of Br and Cl.

i have this so far-

100 * 1.3931= [Br] * 1.4368 + 1.3785 * [Cl]

thanks!

Answer 1

Yes, and the second equation is that the sum of both percents is 100. So replace the percent Cl with (100-Br), and solve for Br percent.

Answer 2

Am I missing something here?
I get a negative number. Isn't it supposed to be
100*1.3931 = 1.3785*Br + 1.4368*Cl