146. Solving a chemistry problem

11. When measuring the viscosity of solutions of polyisoprene in toluene using a capillary viscometer, the following data were obtained:
 
Concentration C, g / dm 3 0 1 1.94 2.59 3.24 3.89
The solution flow time τ, from 165.2 214.3 273.0 322.5 378.2 437.0
Calculate the specific and reduced viscosity of solutions. Construct a graph of the dependence ηd / C = f (C) and determine the characteristic
viscosity of the solution [η].