Exactly of hydrogen gas and of chlorine gas are allowed to react completely to form hydrogen chlorid — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question
Question
Exactly $10\text{ mL}$ of hydrogen gas and $12.5\text{ mL}$ of chlorine gas are allowed to react completely to form hydrogen chloride gas ($H_2 + Cl_2 \rightarrow 2HCl$). Under identical conditions of temperature and pressure, what will be the exact total volume (in $\text{mL}$) of the final gaseous mixture left in the container?
💡 Solution & Explanation
According to Gay-Lussac's Law of combining volumes, gases react in simple whole-number ratios of their volumes. Reaction: $H_2(g) + Cl_2(g) \rightarrow 2HCl(g)$. Initial Volumes: $10\text{ mL}$ of $H_2$, $12.5\text{ mL}$ of $Cl_2$. The stoichiometry is 1 volume $H_2$ : 1 volume $Cl_2$ : 2 volumes $HCl$. $10\text{ mL}$ of $H_2$ will completely consume $10\text{ mL}$ of $Cl_2$ to produce $20\text{ mL}$ of $HCl$. $H_2$ is the limiting reactant. Volume of unreacted $Cl_2 = 12.5 - 10 = 2.5\text{ mL}$. Volume of $HCl$ formed = $20\text{ mL}$. Total volume of the final gaseous mixture = $20\text{ mL } HCl + 2.5\text{ mL } Cl_2 = 22.5\text{ mL}$.