What will be the volume of $O_2$ gas at $STP$ for complete combustion of $7.8 \ g$ acetylene? ............ $L$

For the reaction $2Al_{(s)} + 6HCl_{(aq)} \rightarrow 2Al^{3+}_{(aq)} + 6Cl^{-}_{(aq)} + 3H_{2_{(g)}}$,which of the following statements is correct?

For the combustion reaction $C_2H_{6(g)} + nO_{2(g)} \to CO_{2(g)} + H_2O_{(l)}$,what is the ratio of the stoichiometric coefficients of $CO_2$ and $H_2O$ in the balanced equation?

Combustion of glucose $(C_6H_{12}O_6)$ produces $CO_2$ and water. The amount of oxygen (in $g$) required for the complete combustion of $900 \ g$ of glucose is:
[Molar mass of glucose in $g \ mol^{-1} = 180$]

The vapour density of a certain gas is $16$. What is the volume occupied by $8 \ g$ of gas at $STP$ assuming ideal behaviour (in $dm^3$)?

At $400 \ K$,$1 \ mol$ of a hydrocarbon is completely burned. It produces $132 \ g$ of a gas along with $72 \ g$ of water vapour. The hydrocarbon is: