101. Solving a chemistry problem

623. Silica Sol Seaton (trademark) was studied by turbidimetry with the following results:
s, g/l 18.9 35.9 70.8 140.1
n, m–1 1.49 2.29 3.30 4.32
at a light wavelength of 546.1 nm, a light refractive index in the solvent of 1.3345, and a refractive index increment of 0.0638 cm3/g. Calculate the radius of the sol particles from these data, assuming the density of silica is 2.20 g/cm3.