The weight percentage of $C$ and $H$ in a hydrocarbon is in the ratio of $4: 1$. What is its empirical formula?

An organic compound gave $C = 92.31\%$ and $H = 7.69\%$. If the molecular weight of the compound is $78$,its molecular formula is

The empirical formula of a compound is $CH_2O$ and its molecular mass is $180$. The molecular formula of this compound is .....

Complete combustion of $1.80 \, g$ of an oxygen-containing compound $(C_xH_yO_z)$ gave $2.64 \, g$ of $CO_2$ and $1.08 \, g$ of $H_2O$. The percentage of oxygen in the organic compound is

$A$ sample of a hydrate of barium chloride weighing $61 \ g$ was heated until all the water of hydration was removed. The dried sample weight is $52 \ g$. The formula of the hydrated salt is: (atomic mass: $Ba = 137 \ amu, Cl = 35.5 \ amu$)

$A$ gaseous hydrocarbon gives upon combustion $0.72 \ g$ of water and $3.08 \ g$ of $CO_{2}$. The empirical formula of the hydrocarbon is: