At Boyle's temperature, the compressibility factor $\mathrm{Z}$ for a real gas is

The isotherms of a gas are shown below :

Among the following,

(i) At ${\mathrm{T}}_1$, the gas cannot be liquefied

(ii) At point $\mathrm{B}$, liquid starts to appear at ${\mathrm{T}}_2$

(ii) ${\mathrm{T}}_{\mathrm{C}}$ is the highest temperature at which the gas can be liquefied

(iv) At point $\mathrm{A}$, a small increase in pressure condenses the whole system to a liquid

The correct statements are :

In thermodynamics, the $\mathrm{P}-\mathrm{V}$ work done is given by $\mathrm{w}=-\int {\mathrm{dVP}}_{\mathrm{ext}}$. For a system undergoing a particular process, the work done is,

$\mathrm{w}=-\int \mathrm{dV}\left(\frac{\mathrm{RT}}{\mathrm{V}-\mathrm{b}}-\frac{\mathrm{a}}{{\mathrm{V}}^2}\right)$. This equation is applicable to a