We plan to remove dilute sulphuric acid and dilute \(\mathrm{HCl}\) from crushed rock by washing it with water in a continuous countercurrent process with five equilibrium stages. The feed is \(1000.0 \mathrm{~kg} / \mathrm{h}\) (dry, crushed) rock that entrains the same amount of underflow liquid as the other four stages. The porosity of the settled rock is \(\varepsilon=0.70\). The initial weight fraction of sulphuric acid in the underflow liquid is \(\mathrm{x}_{\mathrm{S}, 0}=0.013\), and the initial weight fraction of hydrochloric acid is \(\mathrm{x}_{\mathrm{HCl}, 0}=0.018\). We want to reduce the sulphuric acid final weight fraction to \(\mathrm{x}_{\mathrm{S}, \mathrm{N}}=0.001\) or less, and we want to reduce the \(\mathrm{HCl}\) weight fraction to \(\mathrm{x}_{\mathrm{HCl} . \mathrm{N}}=0.002\) or less. (One of the solutes should be exactly at the specified weight fraction, and the other solute should be at a lower weight fraction.) Find the required overflow flow rate in \(\mathrm{kg} / \mathrm{h}\) and the value of \(\mathrm{x}_{\mathrm{N}}\) for the solute that is below its maximum weight fraction. The entering wash water is pure. Data: Density of dry crushed rock \(ho_{\mathrm{s}}=2.6 \mathrm{~kg} / \mathrm{L}\). Density of overflow fluid \(ho_{\mathrm{f}}=1.0 \mathrm{~kg} / \mathrm{L}\) (assume constant).