For the complete combustion of $1 \, mol$ of a compound with the molecular formula $C_xH_yO_z$,the number of moles of $O_2$ required is:

$16.8 \ L$ of a gas mixture containing $H_2$ and $O_2$ is formed at $NTP$ by the electrolysis of water. What is the mass of the electrolysed water in $g$?

In a chemical reaction,the sum of the formula weight of all reactants is $274 \ u$ and the atom economy is $50 \%$. Calculate the formula weight of the desired product. (in $u$)

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 $mL$)?
$HgO + 4 I^{-} + H_2O \longrightarrow HgI_4^{2-} + 2 OH^{-}$

$H_2$ evolved at $STP$ on complete reaction of $27 \ g$ of Aluminium with excess of aqueous $NaOH$ would be $............ \ L$

Calculate the amount of $NO_2$ required for producing $4$ moles of $HNO_3$ as per the chemical reaction,$3 NO_2 + H_2O \longrightarrow 2 HNO_3 + NO$. (in $g$)