If $\bar{M}_w$ is the weight average molecular weight and $\bar{M}_n$ is the number average molecular weight…
If $\bar{M}_w$ is the weight average molecular weight and $\bar{M}_n$ is the number average molecular weight of a polymer, the poly dispersity index (PDI) of the polymer is given by
$\frac{\bar{M}_n}{\bar{M}_w}$
$\frac{\bar{M}_w}{\bar{M}_n}$
$\bar{M}_w \times \bar{M}_n$
$\frac{1}{\bar{M}_w \times \bar{M}_n}$
Solution
The ratio of weight average molecular weight and the number average molecular weight is called poly dispersity index (PDI).
$
\mathrm{PDI}=\frac{\bar{M}_w}{\bar{M}_n}
$
where,
$\bar{M}_w=$ weight average molecular weight
$\bar{M}_n=$ number average molecular weight
PDI is unity for natural monodispersed polymer but for synthetic polymers it is always greater than unity