The mass average molecular mass & number average molecular mass of a polymer are respectively 40,000 and 30,000. The polydispersity index of polymer will be ?

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A sample of polymer contains 30% molecules with molecular mass 20,000, 40% with molecular mass 30,000 and 30% with molecular mass 60,000. What is the number average molecular mass of the polymer?

The correct option is C 36,000The number average molecular mass of the polymer: M=ΣMiNiΣNi=30(20000)+40(30000)+30(60000)30+40+30=36000Hence, option B is correct.

A sample of polymer contains $30 %$ molecules with molecular mass $20, 000$ , $40 %$ with molecular mass $30, 000$ and $30 %$ with molecular mass $60, 000$ . What is the number average molecular mass of the polymer?

The correct option is C $36, 000$
The number average molecular mass of the polymer:
$M = \frac{Σ M_{i} N_{i}}{Σ N_{i}}$
$= \frac{30 (20000) + 40 (30000) + 30 (60000)}{30 + 40 + 30}$
$= 36000$
Hence, option $B$ is correct.