Which of the following contains the maximum number of carbon atoms?

The density of a gas at $STP$ is $2.86 \, g \, L^{-1}$. Which of the following is the gas?

At $300 \ K$ and $1 \ atm$,$15 \ mL$ of a gaseous hydrocarbon requires $375 \ mL$ of air containing $20 \% \ O_2$ by volume for complete combustion. After combustion,the gases occupy $330 \ mL$. Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure,the formula of the hydrocarbon is:

Thermite is a mixture of $X$ parts of ferric oxide and $Y$ parts of aluminium powder. What are $X$ and $Y$ respectively?

Number of moles of methane required to produce $22 \ g$ $CO_{2(g)}$ after combustion is $x \times 10^{-2}$ moles. The value of $x$ is

Equal weights of methane and oxygen are mixed in an empty container at $25\,^{\circ}C$. The fraction of the total pressure exerted by oxygen is