Which of the following expressions does not represent equation of state of an ideal gas?

 The following expressions does not represent equation of state of an ideal gas is $p=\rho RT$.

The standard equation of the ideal gas is, $pv=nRT$. Where, $\mathrm{p}, \mathrm{v}, \mathrm{n}, \mathrm{R}$and$\mathrm{T}$ are the pressure, volume, number of mole, universal gas constant and temperature.

An ideal gas is a fictitious gas that, because of its tiny size and lack of interactions, perfectly complies with the gas laws. Ideal gas is a gas that abides by all gas laws at all pressures and temperatures.

Hence option C is correct.