Question #44806

The condensation reaction between benzaldehyde (\ce{C6H5CHO}, $0.80 \text{ M}$) and $n$-hexylamine (\ce{C6H13NH2}, $0.30 \text{ M}$) to form a Schiff base is carried out at $298 \text{ K}$ in a buffered solvent system at an optimal pH of $4.5$. The reaction is catalyzed by a saturated solid surface, exhibiting zero-order overall kinetics with a rate constant $k = 3.0 \times 10^{-3} \text{ M min}^{-1}$. The formed Schiff base continuously precipitates out, preventing any backward hydrolysis. At $t = 50 \text{ min}$, a small volume of concentrated \ce{HCl} is injected, abruptly lowering the pH of the medium to $1.0$ (assume negligible volume change). What is the concentration of the unreacted $n$-hexylamine remaining in the solution at $t = 100 \text{ min}$?