The density of $SO_2$ at $STP$ is ......... $g/L$.

What is the mass of $33.6 \ dm^3$ of methane gas at $S.T.P.$?

Sodium oxide reacts with water to produce sodium hydroxide. $20.0 \ g$ of sodium oxide is dissolved in $500 \ mL$ of water. Neglecting the change in volume,the concentration of the resulting $NaOH$ solution is $........ \times 10^{-1} \ M.$ (Nearest integer)
[Atomic mass $: Na=23.0, O=16.0, H=1.0]$

$60 \ mL$ $NaOH$ solution is required for complete neutralization of $0.98 \ g$ orthophosphoric acid. The concentration of $NaOH$ solution is ............. $M$.

Calculate the amount of water $(g)$ produced by the combustion of $16 \ g$ of methane. (in $g$)

Formation of polyethylene from calcium carbide takes place as follows:
$CaC_2 + 2H_2O \to Ca(OH)_2 + C_2H_2$
$C_2H_2 + H_2 \to C_2H_4$
$n(C_2H_4) \to (-CH_2-CH_2-)_n$
The amount of polyethylene obtained from $64.1 \ kg$ of $CaC_2$ is......$kg$.