Question

27 Number average molecular mass of a polymer
that contains 15 molecules with each of mass
8,000 and 15 molecules with each of mass
80,000 is
1) 22,000
2) 33,000
3) 11,000
4) 44.000
28. Which one of the following monomers can not
be used for the cationic polymerisation ?
1) Vinyl ester 2) Isobutylene
3) Vinyl ether 4) Styrene
​

Answer 1

Answer:

11000 because 27mole are there

Answer 2

Answer:

1. The average molecular mass of the polymer is 44000.
2. Vinyl ester can not be used for catatonic polymerisation.

Explanation:

1) Given:

Number of molecules with mass 8000=15

Number of molecules with mass 80000=15

To find: Number average molecular mass=?
Solution:
Total number of molecules(T)=15+15=30

Total mass(M)=15(8000)+15(80000)=15(8000+80000)

We know that,

Number average molecular mass=$\frac{T}{M}$

=15(8000+80000)/30=44000

Therefore, the average molecular mass of the polymer is 44000.

2)

• Among the given molecules, Vinyl ester tends to be electron-donating.
• Compounds with the ability to donate electrons undergo cationic polymerization.
• Therefore, Vinyl ester can not be used for catatonic polymerisation.