If overline M W is the weight average molecular weight and overline M n is the number average molecular weight of a polymer, the poly dispersity index (PDI) of the polymer is given by:

Question

If overline M W is the weight average molecular weight and overline M n is the number average molecular weight of a polymer, the poly dispersity index (PDI) of the polymer is given by: (A) ( overline M n / overline M w ) (B) ( overline M w / overline M n ) (C)  overline M w × overline M n (D) (1/ overline M w × overline M n )

Tardigrade Admin · Accepted Answer

The ratio of weight average molecular weight and the number average molecular weight is called polydispersity index (PDI).

P D I = \frac{M ˉ _{w}}{M ˉ _{n}}

where,

\overline{M}_{w} =

weight average molecular weight

\overline{M}_{n} =

number average molecular weight
PDI is unity for natural monodiapersed polymer but for synthetic polymers it is always greater than unity.

Q. If $\overline{M_{W}}$ is the weight average molecular weight and $\overline{M_{n}}$ is the number average molecular weight of a polymer, the poly dispersity index (PDI) of the polymer is given by:

$\frac{M _{n}}{M _{w}}$

$\frac{M _{w}}{M _{n}}$

$\overline{M_{w}} \times \overline{M_{n}}$

$\frac{1}{M _{w} \times M _{n}}$

Q. If MW​​ is the weight average molecular weight and Mn​​ is the number average molecular weight of a polymer, the poly dispersity index (PDI) of the polymer is given by:

Mw​​Mn​​​

Mn​​Mw​​​

Mw​​×Mn​​

Mw​​×Mn​​1​

Q. If $\overline{M_{W}}$ is the weight average molecular weight and $\overline{M_{n}}$ is the number average molecular weight of a polymer, the poly dispersity index (PDI) of the polymer is given by:

$\frac{M _{n}}{M _{w}}$

$\frac{M _{w}}{M _{n}}$

$\overline{M_{w}} \times \overline{M_{n}}$

$\frac{1}{M _{w} \times M _{n}}$