How many gram-equivalents of $NaOH$ are required to neutralize $25 \ cm^{3}$ of a decinormal $HCl$ solution?

The heat of combustion of methane is given by the following equation. How many grams of methane are required to produce $445 \ kJ$ of heat (in $g$)?
$CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O \ (\Delta H = -891 \ kJ/mol)$

For a gaseous reaction $Cl_{2(g)} + PCl_{3(g)} \to PCl_{5(g)}$. If $10 \ mL$ of $Cl_2$ completely react with $PCl_3$,then find out the produced volume of $PCl_5$ in $mL$.

What volume (in $mL$) of $0.1 \ M \ KOH$ solution is required for the complete neutralization of $20 \ mL$ of $0.1 \ M$ phosphorous acid $(H_3PO_3)$?

If a rocket runs on a fuel $(C_{15}H_{30})$ and liquid oxygen,the weight of oxygen required and $CO_{2}$ released for every litre of fuel respectively are: (Given: density of the fuel is $0.756 \ g/mL$)

$X \ g$ of $Ag$ is dissolved in $HNO_3$ and this solution is treated with excess $NaCl$. If $2.87 \ g$ of $AgCl$ precipitate is obtained,then the value of $X$ is ............. $g$.