Question

The unit of $a$ in Vander Waals' equation
$\left(P+\frac{a{n}^2}{V^2}\right)(V-nb)=nRT$ is:

• A. $atm{L}^{2}mo{l}^{-2}$
• B. $atm{L}^{3}mo{l}^{-2}$
• C. $atmLmo{l}^{-2}$
• D. $atm{L}^{2}mo{l}^{-1}$

Answer 1

The correct option is A $atm{L}^{2}mo{l}^{-2}$

Pressure correction, $P^{\prime }=\frac{n^{2}a}{V^2}$

$a=\frac{P^{\prime }{V}^2}{n^2}=\frac{Pressurecorrection\times Volum{e}^2}{Mo{l}^2}$

$=\frac{atm\times L^2}{mo{l}^2}=atm{L}^{2}mo{l}^{-2}$