For the dissolution of platelets in dilute solution with independent dissolution mass transfer coefficients for the flat and growth sides,

a. Show that

\[ \begin{aligned} & h=-2 k_{\text {flat }} ho_{\text {liquid }}\left(x_{A, \text { solubility,mass }}-x_{A, \text { bulk,mass }}\right) t / ho_{\text {solid }}+h_{\text {initial }} \\ & L=-2 k_{\text {growth sides }} ho_{\text {liquid }}\left(x_{\text {A,solubility,mass }}-x_{A, \text { bulk,mass }}\right) t / ho_{\text {solid }}+L_{\text {initial }} \end{aligned} \]

b. If \(\mathrm{k}_{\text {flat }}\) and \(\mathrm{k}_{\text {growth sides }}\) are the same order of magnitude, determine \(\mathrm{L}\) value when platelet disappears.