Question $2$

$[18]$

Calculate the time $)$ required for the sublimation of $1g$ of naphthalene from a naphthalene ball of mass $2g$ suspended in a large volume of stagnant air at $50C$ and $1\mathrm{.}013$ bar pressure. The diffusivity of naphthalene in air under the given conditions is $7\mathrm{.}15{10}^6\frac{m^2}{s},$ and $k_G$ value reported as $0\mathrm{.}0315mo\frac{l}{m^2}.$ s bar. The naphthalene density is $1130k\frac{g}{m^3}$ and its sublimation pressure at $50C$ is $0\mathrm{.}87mmHg.$ The molecular mass of naphthalene is $128.$ Also calculate the film thickness $($mm$).$