Cyclopentane, a commonly used solvent in chemical processes, is stored in a high$-$pressure

vessel at $275$ bar and $110C.$ The vapor pressure of cyclopentane at $110C$ is measured to be

$5\mathrm{.}267$ bar.

$($a$)$ Estimate the fugacity of cyclopentane at $110C$ and $275$ bar.

$($b$)$ Discuss the significance of fugacity in the practical design and operation of high$-$pressure

systems involving volatile substances like cyclopentane.