When $2$ moles of an alkane undergo complete combustion, $400\ \text{dm}^3$ of carbon dioxide are formed at $301\ \text{K}$ and $1 \times 10^5\ \text{Pa}$. Under these conditions, carbon dioxide may be treated as an ideal gas. What is the formula of the alkane?
- A$\text{C}_8\text{H}_{18}$
- B$\text{C}_{16}\text{H}_{34}$
- C$\text{C}_{20}\text{H}_{42}$
- D$\text{C}_{40}\text{H}_{82}$