The osmotic pressure ($\pi$) of a polymer sample at different concentrations ($c$) was measured at $T(K)$. A plot of $(\pi/c)$ versus c gave a straight line with slope ($m$) and intercept ($c'$). The number average molecular weight of the ploymer is ($R=$ gas constant).
(a)$dfrac{R t}{c'}$
(b)$\frac{c^{\prime}}{R T}$
(c)RT
(d)mRT
Answer
Answer (as printed): B
Explanation
Osmotic pressure, $\pi = C_1 RT(1+BC_1+\cdots)$ where $C_1$ = concentration of polymer in $\mathrm{mol\,L^{-1}}$ unit and $B$ = constant. When concentration is expressed in terms of $c$ ($\mathrm{g\,L^{-1}}$) then, $C_1 = Mc$