Under review — part of this question (a structure or an option) is not clear in the source scan. 4AB is checking it against the original book; the answer shown may change.
The addition polymerization of M (monomer) involves the following stages: (I=initiator, R=free radical)
\[ \begin{array}{l} I \xrightarrow{k_1} R \quad \text{(initiation)} \\ R+M \xrightarrow{k_2} RM \\ RM+M \rightarrow RM_2 \ \text{and so on} \\ RM_n + M_n, R \xrightarrow{k_2} R-M_n-M_{n'}-R \end{array} \]
The rate constant for free radical formation is $2\times10^{-3}\,\mathrm{s^{-1}}$. The initial concentration of initiator is $10^{-3}\,\mathrm{mol\,dm^{-3}}$. The overall rate of the reaction is $4\times10^{-1}\,\mathrm{mol\,dm^{-1}\,s^{-1}}$. Assuming steady state approximation for free radical, the kinetic chain length is:
(a)2000
(b)$8\times10^{9}$
(c)20
(d)200
Answer
Under review — not yet confirmed.
Answer (as printed): A
Explanation
6789 :; <6:<7=78>:? Kinetic chain length= @ABC DE F(FBFABFD( 6789 :; 697H8>:? N×PQRS TDUVTRS W RX = = = 2000 IJ [L] (Z×PQRS W RX )(PQRS TDUVTRS )