Q31 / 160 · AP EAMCET 2019 (23 Apr Shift 1) · Chemistry

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

  • A
    22,000
  • B
    33,000
  • C
    11,000
  • Correct answer
    D
    44,000

Solution

Number average molecular mass of polymer is given by formula: \(\begin{aligned} M_n & =\frac{\Sigma N_i M_i}{\Sigma N_i} \\ & =\frac{15 \times 8000+15 \times 80,000}{30} \\ & =\frac{120000+1200000}{30} \\ & =\frac{1320000}{30}=44,000 \end{aligned}\)

Hence, the correct answer is option: 'D'.

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