Paper: CSIR-NET June 2016 · Subject: Physical Chemistry · Chapter: Polymer Chemistry · Topic: Polymer Chemistry – General · Marks: 2 · Difficulty: Medium
The condensation of hydroxy acid produces a polyster with the probability of linkage at both ends being p . The mole fraction of k-mer chain formation is
(a)$\mathrm{p}^{\mathrm{k}}$
(b)$p(1-p)^{k-1}$
(c)$p^{k-1}(1-p)$
(d)$\mathrm{p}_{\mathrm{k}-1}$
Answer
Answer: C ✓ checked by 4AB · confidence high
The source book printed D; on checking, C is correct — see the explanation.
Printed D omits the (1 − p) factor for the chain end.
Explanation
A k-mer needs k − 1 formed links (probability p each) and one unreacted end (1 − p): mole fraction p^{k−1}(1 − p) (Flory).