Question

Polydispersity index is defined as ______ where Mw and Mn are the weight average and number average molecular masses respectively.

(a) Mw x Mn

(b) Mw/Mn

(c) Mn/Mw

(d) Mw – Mn

This question was posed to me during a job interview.

The question is from Molecular Mass of Polymers in division Polymers of Chemistry – Class 12

Answer 1

Correct answer is (b) Mw/Mn

The explanation: Polydispersity index (PDI) is defines as the ratio of weight average molecular mass to the number average molecular mass. It gives an idea of the homogeneity of the polymer.