If the density of methanol is $0.793 \ kg \ L^{-1}$,what volume is needed to prepare $2.5 \ L$ of a $0.25 \ M$ solution (in $mL$)?

As per the following equation, $0.217 \ g$ of $HgO$ (molecular mass $= 217 \ g \ mol^{-1}$) reacts with excess iodide. On titration of the resulting solution, how many $mL$ of $0.01 \ M$ $HCl$ is required to reach the equivalence point (in $mL$)?
$HgO + 4 I^{-} + H_2O \longrightarrow HgI_4^{2-} + 2 OH^{-}$

$A$ $250 \, mL$ solution of $Na_2CO_3$ contains $2.65 \, g$ of $Na_2CO_3$. If $10 \, mL$ of this solution is taken and diluted with distilled water up to $0.1 \, L$,what will be the molarity of the resulting solution (in $, M$)?

Volume of $3 \ M \ NaOH$ (formula weight $40 \ g \ mol^{-1}$) which can be prepared from $84 \ g$ of $NaOH$ is $ . . . . . . \times 10^{-1} \ dm^3$.

$3 \ L$ mixture of $C_2H_6$ and $C_3H_8$ produces $8 \ L$ of $CO_2$ upon complete combustion. Find the volume of $C_2H_6$ in the mixture.

How many grams of iron are theoretically produced by the reduction of $1 \ kg$ of $Fe_2O_3$?