The osmotic pressure $(\pi)$ of a polymer sample at different concentrations $(\mathrm{c})$ was measured at T(K). A plot of $(\pi / \mathrm{c})$ versus c gave a straight line with slope (m) and intercept (c'). The number average molecular weight of the polymer is ( $\mathrm{R}=$ gas constant).
(a)$\frac{\mathrm{Rt}}{\mathrm{c}^{\prime}}$
(b)$\frac{\mathrm{c}^{\prime}}{\mathrm{RT}}$
(c)RT
(d)mRT
Answer
Answer: A ✓ checked by 4AB · confidence high
The source book printed B; on checking, A is correct — see the explanation.
Printed B (c′/RT) is the inverse.
Explanation
π/c = RT/M_n + Bc: the intercept c′ = RT/M_n, so M_n = RT/c′.