A volume of $10\,\text{cm}^3$ of hydrogen gas is combined with $x\,\text{cm}^3$ of chlorine gas. The equation for the reaction is given below. $\text{H}_2(g) + \text{Cl}_2(g) \rightarrow 2\text{HCl}(g)$ The hydrogen is completely used up. By the end of the reaction, the total gas volume is $40\,\text{cm}^3$. All measurements are taken at room temperature and pressure. Determine the value of $x$.
- A$10\,\text{cm}^3$
- B$20\,\text{cm}^3$
- C$30\,\text{cm}^3$
- D$40\,\text{cm}^3$